diff --git a/.sisyphus/plans/cron-jobs-package.md b/.sisyphus/plans/cron-jobs-package.md
new file mode 100644
index 0000000..9cacca1
--- /dev/null
+++ b/.sisyphus/plans/cron-jobs-package.md
@@ -0,0 +1,431 @@
+# Plan: Consolidated `jobs` Package for Background Cron Tasks
+
+**Goal:** Extract 9 side-effect cleanup functions from `GetAvailableHours` HTTP handler into a dedicated `jobs` package with cron-scheduled, parallel execution. Remove the lazy-cleanup antipattern.
+
+**Current state:**
+- 9 cleanup functions in `backend/handlers/scheduling/time-blockers.go` — all called synchronously in `default-hours.go:364-407` on every `GET /available-hours` request
+- Only `CleanupOldReservations` ALSO runs on a background goroutine (`main.go:432-450`, 5min ticker)
+- 4 other ad-hoc background goroutines exist (JWT cleanup, GDPR cache, login state, rate limiter)
+- `robfig/cron/v3` v3.0.1 is already a `go.mod` dependency (currently used only for parsing time-blocker cron expressions)
+
+---
+
+## Phase 1: Create `backend/internal/jobs/` Package
+
+**New package:** `crussell/internal/jobs`
+
+### File: `scheduler.go`
+
+Core scheduler abstraction built on `robfig/cron/v3`:
+
+```go
+package jobs
+
+import (
+    "context"
+    "log"
+    "time"
+    "github.com/robfig/cron/v3"
+)
+
+// Job defines a single periodic task.
+type Job struct {
+    Name        string                         // Human-readable name (for logging)
+    Schedule    string                         // Standard cron expression ("*/5 * * * *")
+    Timeout     time.Duration                  // Per-execution timeout
+    Concurrency int                            // Max concurrent runs (0 = unlimited, 1 = serial)
+    Handler     func(context.Context) error     // The actual work
+}
+
+// Scheduler manages all registered cron jobs with parallel execution.
+type Scheduler struct {
+    cron       *cron.Cron
+    entries    []cron.EntryID
+    registry   []Job
+    baseCtx    context.Context
+    cancel     context.CancelFunc
+    semaphores map[string]chan struct{}     // Per-job concurrency limit
+}
+```
+
+**Key design decisions:**
+1. Each job runs in its own goroutine (cron v3 default) — parallel by nature
+2. Per-job concurrency control via channel semaphore — prevents overlapping runs of the same job
+3. Panic recovery wrapper — matches existing pattern in `jwt.go`, `gdpr_export.go`, `auth/local.go`
+4. Timeout via `context.WithTimeout` — matches existing `main.go` pattern
+5. Graceful shutdown via `baseCtx` — the cron scheduler is stopped, then active jobs drain
+
+```go
+func New() *Scheduler {
+    ctx, cancel := context.WithCancel(context.Background())
+    return &Scheduler{
+        cron:       cron.New(cron.WithLocation(londonLocation)),
+        baseCtx:    ctx,
+        cancel:     cancel,
+        semaphores: make(map[string]chan struct{}),
+    }
+}
+
+func (s *Scheduler) Register(job Job) {
+    // Validate cron expression at registration time
+    parser := cron.NewParser(cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow)
+    if _, err := parser.Parse(job.Schedule); err != nil {
+        log.Fatalf("jobs: invalid cron schedule %q for job %q: %v", job.Schedule, job.Name, err)
+    }
+    s.registry = append(s.registry, job)
+}
+
+func (s *Scheduler) Start() {
+    for _, job := range s.registry {
+        j := job // capture
+        entryID, err := s.cron.AddFunc(j.Schedule, s.wrapJob(j))
+        if err != nil {
+            log.Fatalf("jobs: failed to register %q: %v", j.Name, err)
+        }
+        s.entries = append(s.entries, entryID)
+    }
+    s.cron.Start()
+}
+
+func (s *Scheduler) Shutdown() <-chan struct{} {
+    ctx := s.cron.Stop() // Stop scheduler (returns ctx that completes when all jobs finish)
+    s.cancel()           // Cancel base context so in-flight jobs know to stop
+    return ctx.Done()    // Caller can wait for this
+}
+
+// wrapJob adds panic recovery, timeout, concurrency control, and logging.
+func (s *Scheduler) wrapJob(job Job) func() {
+    // Set up semaphore if concurrency limited
+    var sem chan struct{}
+    if job.Concurrency > 0 {
+        sem = make(chan struct{}, job.Concurrency)
+        sem <- struct{}{} // Initial slot filled
+    }
+
+    return func() {
+        // Concurrency guard
+        if sem != nil {
+            select {
+            case <-sem:
+                // Acquired — proceed
+            default:
+                log.Printf("jobs: %q skipped (previous run still in progress)", job.Name)
+                return
+            }
+            defer func() { sem <- struct{}{} }()
+        }
+
+        // Panic recovery
+        defer func() {
+            if r := recover(); r != nil {
+                log.Printf("jobs: panic recovered in %q: %v", job.Name, r)
+            }
+        }()
+
+        // Timeout
+        ctx, cancel := context.WithTimeout(s.baseCtx, job.Timeout)
+        defer cancel()
+
+        start := time.Now()
+        if err := job.Handler(ctx); err != nil {
+            log.Printf("jobs: %q failed: %v (duration: %v)", job.Name, err, time.Since(start))
+        } else {
+            log.Printf("jobs: %q completed (duration: %v)", job.Name, time.Since(start))
+        }
+    }
+}
+```
+
+### File: `cleanup.go`
+
+Registration of all 9 scheduling cleanup functions + JWT cleanup.
+
+```go
+package jobs
+
+import (
+    "context"
+    "crussell/auth"
+    "crussell/handlers/scheduling"
+    "time"
+)
+
+// RegisterAll registers every background job.
+func RegisterAll(s *Scheduler) {
+    // === HIGH FREQUENCY (every 5 min) ===
+
+    s.Register(Job{
+        Name:        "cleanup-reservations",
+        Schedule:    "*/5 * * * *",
+        Timeout:     30 * time.Second,
+        Concurrency: 1,
+        Handler:     scheduling.CleanupOldReservations,
+    })
+
+    s.Register(Job{
+        Name:        "cleanup-expired-deposits",
+        Schedule:    "*/5 * * * *",
+        Timeout:     30 * time.Second,
+        Concurrency: 1,
+        Handler:     scheduling.CleanupExpiredDeposits,
+    })
+
+    // === MID FREQUENCY (hourly) ===
+
+    s.Register(Job{
+        Name:        "cleanup-expired-loyalty-redemptions",
+        Schedule:    "0 * * * *",
+        Timeout:     30 * time.Second,
+        Concurrency: 1,
+        Handler:     scheduling.CleanupExpiredLoyaltyRedemptions,
+    })
+
+    s.Register(Job{
+        Name:        "cleanup-old-idempotency-keys",
+        Schedule:    "0 * * * *",
+        Timeout:     30 * time.Second,
+        Concurrency: 1,
+        Handler:     scheduling.CleanupOldIdempotencyKeys,
+    })
+
+    s.Register(Job{
+        Name:        "cleanup-revoked-jtis",
+        Schedule:    "0 * * * *",
+        Timeout:     30 * time.Second,
+        Concurrency: 1,
+        Handler: func(ctx context.Context) error {
+            auth.CleanupRevokedJTIs(ctx)
+            return nil
+        },
+    })
+
+    // === LOW FREQUENCY (daily, off-peak) ===
+
+    s.Register(Job{
+        Name:        "anonymize-stale-guest-accounts",
+        Schedule:    "0 3 * * *",           // 3am
+        Timeout:     5 * time.Minute,
+        Concurrency: 1,
+        Handler:     scheduling.AnonymizeStaleGuestAccounts,
+    })
+
+    s.Register(Job{
+        Name:        "cleanup-expired-financial-records",
+        Schedule:    "0 4 * * *",           // 4am
+        Timeout:     10 * time.Minute,
+        Concurrency: 1,
+        Handler:     scheduling.CleanupExpiredFinancialRecords,
+    })
+
+    s.Register(Job{
+        Name:        "cleanup-expired-gift-cards",
+        Schedule:    "0 5 * * *",           // 5am
+        Timeout:     5 * time.Minute,
+        Concurrency: 1,
+        Handler:     scheduling.CleanupExpiredGiftCards,
+    })
+
+    s.Register(Job{
+        Name:        "cleanup-idle-accounts",
+        Schedule:    "30 3 * * *",          // 3:30am (offset from financial)
+        Timeout:     5 * time.Minute,
+        Concurrency: 1,
+        Handler:     scheduling.CleanupIdleAccounts,
+    })
+
+    s.Register(Job{
+        Name:        "cleanup-old-name-history",
+        Schedule:    "30 4 * * *",          // 4:30am
+        Timeout:     30 * time.Second,
+        Concurrency: 1,
+        Handler:     scheduling.CleanupOldNameHistory,
+    })
+}
+```
+
+**Staggering rationale:** Daily jobs at 3am/3:30am/4am/4:30am/5am spread the load so heavy operations (financial aggregation, idle account scans) don't contend with each other or with the hourly jobs. High-frequency jobs (reservations, deposits) are decoupled on their own 5-min schedules.
+
+---
+
+## Phase 2: Wire into `main.go`
+
+### Before:
+```go
+// main.go:142
+auth.StartJTICleanup()
+
+// main.go:432-450 (background goroutine for reservations)
+cleanupCtx, cleanupStop := context.WithCancel(context.Background())
+go func() {
+    ticker := time.NewTicker(reservationCleanupInterval)
+    ...
+}()
+
+// main.go:457-468 (shutdown)
+cleanupStop()
+```
+
+### After:
+```go
+// At package level, after constants but before init()
+var sched *jobs.Scheduler
+
+// In main(), after initDB()/initSquare()/etc but before r := chi.NewRouter():
+sched = jobs.New()
+jobs.RegisterAll(sched)
+sched.Start()
+
+// In main(), shutdown block (replace the old cleanupStop() call):
+quit := make(chan os.Signal, 1)
+signal.Notify(quit, syscall.SIGTERM, syscall.SIGINT)
+go func() {
+    <-quit
+    log.Println("Shutting down server...")
+    
+    // Graceful HTTP shutdown
+    ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
+    defer cancel()
+    if err := srv.Shutdown(ctx); err != nil {
+        log.Printf("Server forced to shutdown: %v", err)
+    }
+    
+    // Graceful job scheduler shutdown
+    <-sched.Shutdown()
+    log.Println("Background jobs stopped")
+}()
+```
+
+**Remove:**
+- `reservationCleanupInterval` and `reservationCleanupTimeout` constants (`main.go:71-72`)
+- `cleanupCtx`/`cleanupStop` variables (`main.go:433`)
+- The goroutine block (`main.go:434-450`)
+- Import `scheduling` from `main.go` (no longer needed there)
+- `auth.StartJTICleanup()` call (`main.go:142`)
+
+---
+
+## Phase 3: Remove Side-Effects from `GetAvailableHours`
+
+**File: `backend/handlers/scheduling/default-hours.go`**
+
+Delete lines 364-407 (the entire cleanup block):
+
+```diff
+-	// Clean up old reservations (older than 1 hour)
+-	if err := CleanupOldReservations(r.Context()); err != nil {
+-		log.Printf("Failed to cleanup old reservations: %v", err)
+-	}
+-
+-	// Anonymize stale guest accounts (6+ months after last booking)
+-	if err := AnonymizeStaleGuestAccounts(r.Context()); err != nil {
+-		log.Printf("Failed to anonymize stale guest accounts: %v", err)
+-	}
+-
+-	// Clean up expired loyalty redemptions (pending past expires_at)
+-	if err := CleanupExpiredLoyaltyRedemptions(r.Context()); err != nil {
+-		log.Printf("Failed to cleanup expired loyalty redemptions: %v", err)
+-	}
+-
+-	// Clean up expired financial records (aggregate + delete granular data)
+-	if err := CleanupExpiredFinancialRecords(r.Context()); err != nil {
+-		log.Printf("Failed to cleanup expired financial records: %v", err)
+-	}
+-
+-	// Clean up bookings past deposit deadline (no deposit paid)
+-	if err := CleanupExpiredDeposits(r.Context()); err != nil {
+-		log.Printf("Failed to cleanup expired deposits: %v", err)
+-	}
+-
+-	// Clean up expired gift cards (unused for 24+ months)
+-	if err := CleanupExpiredGiftCards(r.Context()); err != nil {
+-		log.Printf("Failed to cleanup expired gift cards: %v", err)
+-	}
+-
+-	// Clean up idle accounts (2yr no money, 5yr with money)
+-	if err := CleanupIdleAccounts(r.Context()); err != nil {
+-		log.Printf("Failed to cleanup idle accounts: %v", err)
+-	}
+-
+-	// Clean up old idempotency keys (24h+ and non-pending)
+-	if err := CleanupOldIdempotencyKeys(r.Context()); err != nil {
+-		log.Printf("Failed to cleanup old idempotency keys: %v", err)
+-	}
+-
+-	// Clean up old name history (6+ months)
+-	if err := CleanupOldNameHistory(r.Context()); err != nil {
+-		log.Printf("Failed to cleanup old name history: %v", err)
+-	}
+```
+
+Also remove `"log"` import from `default-hours.go` if it becomes unused after removal.
+
+---
+
+## Phase 4: Remove `auth.StartJTICleanup()` (Optional but Recommended)
+
+**File: `backend/auth/jwt.go`**
+
+- Keep `CleanupRevokedJTIs(ctx)` — it's used by tests and now by the jobs package
+- Delete `StartJTICleanup()` entirely (no longer needed, replaced by the jobs package)
+- Remove the ticker goroutine
+
+---
+
+## Phase 5: Update Documentation
+
+**File: `obsidian/Crussell/Technical Manual.md`**
+- Update lines ~545 and ~999: change "lazy cleanup triggered on availability fetch" to "all cleanup runs on cron schedules via the `jobs` package"
+- Remove the lazy-cleanup justification
+- Add a new section documenting the `jobs` package and its job registry
+
+**File: `obsidian/Crussell/Future Work - Gap Backlog.md`**
+- Mark item #2 as fully complete (strikethrough)
+- Remove the note about remaining functions still running on `GET /api/availability`
+
+**File: `README.md`** (optional)
+- Add a line about the background job scheduler
+
+---
+
+## Effort Estimate
+
+| Step | Files Changed | Effort |
+|------|--------------|--------|
+| Phase 1a: `scheduler.go` | 1 new file | 2-3h |
+| Phase 1b: `cleanup.go` | 1 new file | 1h |
+| Phase 2: Wire `main.go` | 1 file | 30min |
+| Phase 3: Remove side-effects from handler | 1 file | 15min |
+| Phase 4: Remove `StartJTICleanup` | 1 file | 15min |
+| Phase 5: Update docs | 2-3 files | 30min |
+| Testing & go vet | — | 1h |
+| **Total** | **4-5 files (+2 new)** | **~6h** |
+
+---
+
+## Risks & Mitigations
+
+| Risk | Mitigation |
+|------|------------|
+| **Concurrent DB load** from multiple jobs at the same cron tick | Stagger daily jobs across 3am-5am range. High-frequency jobs (5min) are lightweight. Per-job `Concurrency: 1` prevents overlapping runs. |
+| **Job takes longer than interval** (e.g., financial aggregation >5min while scheduled every 5min) | `Concurrency: 1` + skip-logic: if previous run still in-flight, the new invocation is skipped and logged. |
+| **Cron expression parsing differs** from existing time-blocker parser | Both use `cron.NewParser(cron.Minute \| cron.Hour \| cron.Dom \| cron.Month \| cron.Dow)` — identical. |
+| **Tests expect cleanup side-effects** from `GetAvailableHours` | Search for tests that rely on the side-effect calls. Some may need an explicit cleanup call before assertions. |
+| **`CleanupExpiredDeposits` timing gap** — deposit-lapsed slots not freed until next cron tick | 5-min frequency is acceptable. The previous behavior freed on the *next* availability fetch, which could be minutes or hours apart depending on user activity. 5-min max latency is actually *better* than the lazy approach during quiet periods. |
+| **Panic in one job takes down the scheduler** | `wrapJob` has defer-recover. One job's panic cannot affect others (separate goroutines). |
+
+---
+
+## Edge Cases & Exclusions
+
+**Not in scope (Phase 1):**
+- `gdpr_export.go:init()` — GDPR cache cleanup (5min ticker). Tightly coupled to package-level state. Leave as-is.
+- `auth/local.go:init()` — Login state cleanup. Tightly coupled. Leave as-is.
+- `mw/ratelimit.go` goroutines — Rate limiter cleanup. Leave as-is.
+- These can be migrated to the scheduler in a follow-up if desired, but require more refactoring.
+
+**Not a concern:**
+- `backend/handlers/scheduling/time-blockers.go` already uses `robfig/cron/v3` — no new dependency, no version conflict.
+- All 9 cleanup functions have signature `func(context.Context) error` — perfectly uniform for the `Job.Handler` type.
+- The `scheduling` package is already imported in `main.go` — no new import needed for that.
+
+**Key invariant:** All cleanup functions are idempotent (documented in code). Running them on cron instead of on-demand has zero correctness impact — they produce the same result regardless of how often they run.
diff --git a/backend/auth/jwt.go b/backend/auth/jwt.go
index 8ee5627..8dd1a8e 100644
--- a/backend/auth/jwt.go
+++ b/backend/auth/jwt.go
@@ -121,7 +121,7 @@ func GenerateToken(userID string, role string) (string, string, error) {
 		return "", "", err
 	}
 
-	_, tokenString, err := TokenAuth.Encode(map[string]interface{}{
+	_, tokenString, err := TokenAuth.Encode(map[string]any{
 		"user_id": userID,
 		"role":    role,
 		"jti":     jti,
@@ -137,7 +137,7 @@ func VerifyToken(tokenString string, ctx context.Context) (userID string, role s
 		return "", "", "", err
 	}
 
-	var uidVal interface{}
+	var uidVal any
 	if err := token.Get("user_id", &uidVal); err != nil {
 		return "", "", "", fmt.Errorf("invalid user_id claim")
 	}
@@ -146,7 +146,7 @@ func VerifyToken(tokenString string, ctx context.Context) (userID string, role s
 		return "", "", "", fmt.Errorf("invalid user_id claim")
 	}
 
-	var roleVal interface{}
+	var roleVal any
 	if err := token.Get("role", &roleVal); err != nil {
 		return "", "", "", fmt.Errorf("invalid role claim")
 	}
@@ -155,7 +155,7 @@ func VerifyToken(tokenString string, ctx context.Context) (userID string, role s
 		return "", "", "", fmt.Errorf("invalid role claim")
 	}
 
-	var jtiVal interface{}
+	var jtiVal any
 	if err := token.Get("jti", &jtiVal); err != nil {
 		return "", "", "", fmt.Errorf("invalid jti claim")
 	}
diff --git a/backend/auth/jwt_test.go b/backend/auth/jwt_test.go
index 2f62c01..7ad6fe2 100644
--- a/backend/auth/jwt_test.go
+++ b/backend/auth/jwt_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package auth
 
diff --git a/backend/auth/testmain_test.go b/backend/auth/testmain_test.go
index 37dcf38..88f91c5 100644
--- a/backend/auth/testmain_test.go
+++ b/backend/auth/testmain_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package auth
 
diff --git a/backend/db/db.go b/backend/db/db.go
index 366b374..468f775 100644
--- a/backend/db/db.go
+++ b/backend/db/db.go
@@ -1,5 +1,4 @@
 //go:build !dev
-// +build !dev
 
 package db
 
diff --git a/backend/db/db_dev.go b/backend/db/db_dev.go
index ab8ce6f..d32ed45 100644
--- a/backend/db/db_dev.go
+++ b/backend/db/db_dev.go
@@ -1,5 +1,4 @@
 //go:build dev
-// +build dev
 
 package db
 
diff --git a/backend/db/db_test.go b/backend/db/db_test.go
index d9c7e3f..9a70270 100644
--- a/backend/db/db_test.go
+++ b/backend/db/db_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package db
 
@@ -178,5 +177,3 @@ func TestGetEnv_ReturnsEmptyWhenUnset(t *testing.T) {
 // =============================================================================
 // Clean-up — restore env after all tests
 // =============================================================================
-
-
diff --git a/backend/db/db_test_init.go b/backend/db/db_test_init.go
index 0cbdb6e..b8b2e49 100644
--- a/backend/db/db_test_init.go
+++ b/backend/db/db_test_init.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package db
 
diff --git a/backend/db/testmain_test.go b/backend/db/testmain_test.go
index 6868eb9..aa1e5c0 100644
--- a/backend/db/testmain_test.go
+++ b/backend/db/testmain_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package db
 
diff --git a/backend/handlers/admin/bookings_extra_test.go b/backend/handlers/admin/bookings_extra_test.go
index 1cc5e56..4a6de29 100644
--- a/backend/handlers/admin/bookings_extra_test.go
+++ b/backend/handlers/admin/bookings_extra_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package admin
 
@@ -9,8 +8,8 @@ import (
 	"time"
 
 	"crussell/clock"
-	"crussell/testutils"
 	"crussell/handlers/bookings"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 )
 
diff --git a/backend/handlers/admin/bookings_fields_test.go b/backend/handlers/admin/bookings_fields_test.go
index 78abff7..826cab2 100644
--- a/backend/handlers/admin/bookings_fields_test.go
+++ b/backend/handlers/admin/bookings_fields_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package admin
 
diff --git a/backend/handlers/admin/bookings_test.go b/backend/handlers/admin/bookings_test.go
index 344b167..169097d 100644
--- a/backend/handlers/admin/bookings_test.go
+++ b/backend/handlers/admin/bookings_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package admin
 
@@ -32,9 +31,9 @@ import (
 
 	"crussell/clock"
 	"crussell/db"
-	"crussell/testutils"
 	"crussell/handlers/bookings"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 
 	"github.com/go-chi/chi/v5"
@@ -2247,7 +2246,6 @@ func TestAdminBookings_Create_WalkIn(t *testing.T) {
 	}
 
 	// Seed working hours so we have a valid booking window
-	
 
 	// Try to create booking with walk-in time (30 minutes from now - less than 1h requirement)
 	// Regular users would be rejected, but admin should succeed
@@ -2291,7 +2289,6 @@ func TestAdminBookings_Create_WalkInWithDeposits(t *testing.T) {
 	}
 
 	// Seed working hours
-	
 
 	// Set user to have outstanding deposits
 	_, err = tx.Exec(ctx, "UPDATE users SET deposits_required = 3 WHERE id = $1", userID)
@@ -2346,7 +2343,6 @@ func TestAdminBookings_Confirm_CompletesWithPayment_ReducesDeposits(t *testing.T
 		t.Fatalf("failed to create test service: %v", err)
 	}
 
-
 	// Set user to have deposits_required = 2
 	_, err = tx.Exec(ctx, "UPDATE users SET deposits_required = 2 WHERE id = $1", userID)
 	if err != nil {
@@ -2427,7 +2423,6 @@ func TestAdminBookings_Confirm_CompletesWithoutPayment_NoReduction(t *testing.T)
 		t.Fatalf("failed to create test service: %v", err)
 	}
 
-
 	// Set user to have deposits_required = 2
 	_, err = tx.Exec(ctx, "UPDATE users SET deposits_required = 2 WHERE id = $1", userID)
 	if err != nil {
@@ -2502,7 +2497,6 @@ func TestAdminBookings_Create_EnforceDepositsFalse_BypassesLimit(t *testing.T) {
 		t.Fatalf("failed to create test service: %v", err)
 	}
 
-
 	// Set user to have deposits_required = 3
 	_, err = tx.Exec(ctx, "UPDATE users SET deposits_required = 3 WHERE id = $1", userID)
 	if err != nil {
@@ -2564,9 +2558,7 @@ func TestAdminBookings_Create_EnforceDepositsFalse_Within24h(t *testing.T) {
 		t.Fatalf("failed to create test service: %v", err)
 	}
 
-
 	// Seed working hours
-	
 
 	// Set user to have deposits_required = 3
 	_, err = tx.Exec(ctx, "UPDATE users SET deposits_required = 3 WHERE id = $1", userID)
@@ -2619,7 +2611,6 @@ func TestAdminBookings_Create_WalkInGuestUser(t *testing.T) {
 	}
 
 	// Seed working hours
-	
 
 	// Create booking for tomorrow
 	tomorrow := clock.Now().Add(24 * time.Hour).Truncate(time.Second)
@@ -2661,7 +2652,6 @@ func TestAdminBookings_Create_WalkInGuestUser(t *testing.T) {
 func TestGetBookingsByCreatedRange(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -2744,7 +2734,6 @@ func TestGetBookingsByCreatedRange(t *testing.T) {
 func TestGetBookingsByCreatedRange_Empty(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -2824,7 +2813,6 @@ func TestGetBookingsByCreatedRange_InvalidFormat(t *testing.T) {
 func TestGetBookingsByCreatedRange_OrderedByCreatedAt(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -2912,7 +2900,6 @@ func TestGetBookingsByCreatedRange_OrderedByCreatedAt(t *testing.T) {
 func TestGetAdminBooking_WithDiscounts(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -3007,7 +2994,6 @@ func createCompletedBookingWithTimeForAdmin(t *testing.T, ctx context.Context, t
 func TestAdminBookings_CreateWithCustomServices(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -3084,7 +3070,6 @@ func TestAdminBookings_CreateWithCustomServices(t *testing.T) {
 func TestAdminBookings_CreateWithCustomAndRegularServices(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -3208,7 +3193,6 @@ func TestAdminBookings_Create_CustomServiceValidation(t *testing.T) {
 
 	// Test 3: custom_service_ids is provided (should succeed — need working hours)
 	t.Run("provides custom_service_ids only", func(t *testing.T) {
-		
 
 		customServiceID, err := fixtures.CreateTestCustomService(tx)
 		if err != nil {
@@ -3322,7 +3306,6 @@ func TestAdminBookings_Confirm_WithCustomOverrides(t *testing.T) {
 func TestAdminBookings_CreateWithCustomServicesAndOverrides(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -3401,7 +3384,6 @@ func TestAdminBookings_CreateWithCustomServicesAndOverrides(t *testing.T) {
 func TestAdminBookings_AdminReserve_WithCustomServices(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	adminID, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
diff --git a/backend/handlers/admin/custom_services.go b/backend/handlers/admin/custom_services.go
index d83effe..a7cb359 100644
--- a/backend/handlers/admin/custom_services.go
+++ b/backend/handlers/admin/custom_services.go
@@ -9,6 +9,7 @@ import (
 	"errors"
 	"net/http"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/go-chi/chi/v5"
@@ -107,7 +108,7 @@ func GetCustomServices(w http.ResponseWriter, r *http.Request) {
 	}
 
 	var dataQuery string
-	var dataArgs []interface{}
+	var dataArgs []any
 
 	if q != "" {
 		dataQuery = `
@@ -115,7 +116,7 @@ func GetCustomServices(w http.ResponseWriter, r *http.Request) {
 			FROM custom_services
 			WHERE name ILIKE $1 OR description ILIKE $1
 		`
-		dataArgs = []interface{}{"%" + q + "%"}
+		dataArgs = []any{"%" + q + "%"}
 
 		dataQuery += " ORDER BY created_at DESC, id DESC LIMIT $" + strconv.Itoa(len(dataArgs)+1)
 		dataArgs = append(dataArgs, perPage+1)
@@ -318,7 +319,7 @@ func UpdateCustomService(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	updates := make(map[string]interface{})
+	updates := make(map[string]any)
 	if req.Name != nil {
 		updates["name"] = *req.Name
 	}
@@ -361,7 +362,7 @@ func UpdateCustomService(w http.ResponseWriter, r *http.Request) {
 	}
 
 	setClauses := make([]string, 0, len(updates))
-	args := make([]interface{}, 0, len(updates)+1)
+	args := make([]any, 0, len(updates)+1)
 	argIdx := 1
 	for field, val := range updates {
 		setClauses = append(setClauses, field+" = $"+strconv.Itoa(argIdx))
@@ -530,9 +531,10 @@ func joinStrings(strs []string, sep string) string {
 	if len(strs) == 0 {
 		return ""
 	}
-	result := strs[0]
+	var result strings.Builder
+	result.WriteString(strs[0])
 	for _, s := range strs[1:] {
-		result += sep + s
+		result.WriteString(sep + s)
 	}
-	return result
+	return result.String()
 }
diff --git a/backend/handlers/admin/custom_services_test.go b/backend/handlers/admin/custom_services_test.go
index a3fef48..a02cbfb 100644
--- a/backend/handlers/admin/custom_services_test.go
+++ b/backend/handlers/admin/custom_services_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package admin
 
@@ -24,8 +23,8 @@ import (
 	"strings"
 	"testing"
 
-	"crussell/testutils"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 
 	"github.com/go-chi/chi/v5"
diff --git a/backend/handlers/admin/discount_campaigns.go b/backend/handlers/admin/discount_campaigns.go
index f3a9250..5ce42b3 100644
--- a/backend/handlers/admin/discount_campaigns.go
+++ b/backend/handlers/admin/discount_campaigns.go
@@ -195,7 +195,6 @@ func GetDiscountCampaigns(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-
 	w.WriteHeader(http.StatusOK)
 
 	if campaigns == nil {
@@ -384,7 +383,6 @@ func CreateDiscountCampaign(w http.ResponseWriter, r *http.Request) {
 		campaign.CreatedBy = &createdByDB.String
 	}
 
-
 	w.WriteHeader(http.StatusCreated)
 	if err := json.NewEncoder(w).Encode(campaign); err != nil {
 		log.Printf("Error encoding campaign: %v", err)
@@ -424,7 +422,7 @@ func UpdateDiscountCampaign(w http.ResponseWriter, r *http.Request) {
 
 	// Build dynamic update query
 	query := "UPDATE discount_campaigns SET updated_at = NOW()"
-	args := []interface{}{}
+	args := []any{}
 	argNum := 1
 
 	if req.Name != nil {
@@ -603,7 +601,6 @@ func UpdateDiscountCampaign(w http.ResponseWriter, r *http.Request) {
 		campaign.CreatedBy = &createdBy.String
 	}
 
-
 	w.WriteHeader(http.StatusOK)
 	if err := json.NewEncoder(w).Encode(campaign); err != nil {
 		log.Printf("Error encoding campaign: %v", err)
@@ -658,9 +655,8 @@ func DeleteDiscountCampaign(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-
 	w.WriteHeader(http.StatusOK)
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"message": "Campaign deleted successfully",
 		"id":      campaignID,
 	})
@@ -774,7 +770,6 @@ func GetCampaignStats(w http.ResponseWriter, r *http.Request) {
 		BookingCount:   bookingCount,
 	}
 
-
 	w.WriteHeader(http.StatusOK)
 	if err := json.NewEncoder(w).Encode(stats); err != nil {
 		log.Printf("Error encoding stats: %v", err)
diff --git a/backend/handlers/admin/discount_campaigns_test.go b/backend/handlers/admin/discount_campaigns_test.go
index bffd73c..7587ef3 100644
--- a/backend/handlers/admin/discount_campaigns_test.go
+++ b/backend/handlers/admin/discount_campaigns_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package admin
 
@@ -15,8 +14,8 @@ import (
 
 	"crussell/clock"
 	"crussell/db"
-	"crussell/testutils"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 
 	"github.com/go-chi/chi/v5"
@@ -24,7 +23,6 @@ import (
 
 var testAdminID string
 
-
 func makeCampaignRequest(handler http.Handler, method, path string, body interface{}, ctx context.Context, adminID string) *httptest.ResponseRecorder {
 	var req *http.Request
 	if body != nil {
diff --git a/backend/handlers/admin/patch_tests.go b/backend/handlers/admin/patch_tests.go
index c6ed710..afe1117 100644
--- a/backend/handlers/admin/patch_tests.go
+++ b/backend/handlers/admin/patch_tests.go
@@ -138,7 +138,7 @@ func UpdatePatchTest(w http.ResponseWriter, r *http.Request) {
 	}
 
 	query := "UPDATE patch_tests SET "
-	args := []interface{}{}
+	args := []any{}
 	i := 1
 
 	if req.Name != nil {
diff --git a/backend/handlers/admin/patch_tests_test.go b/backend/handlers/admin/patch_tests_test.go
index ff9e614..dcf6f2b 100644
--- a/backend/handlers/admin/patch_tests_test.go
+++ b/backend/handlers/admin/patch_tests_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package admin
 
diff --git a/backend/handlers/admin/services_test.go b/backend/handlers/admin/services_test.go
index 2f4fc3b..b54b730 100644
--- a/backend/handlers/admin/services_test.go
+++ b/backend/handlers/admin/services_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package admin
 
@@ -19,9 +18,9 @@ import (
 	"net/http"
 	"testing"
 
-	"crussell/testutils"
 	"crussell/handlers/services"
 	"crussell/mw"
+	"crussell/testutils"
 )
 
 // TestAdminServices_Create verifies that an admin can create a new service
diff --git a/backend/handlers/admin/settings.go b/backend/handlers/admin/settings.go
index 9a1300a..43cad2d 100644
--- a/backend/handlers/admin/settings.go
+++ b/backend/handlers/admin/settings.go
@@ -8,6 +8,7 @@ import (
 	"net/http"
 	"net/url"
 	"strconv"
+	"strings"
 )
 
 type BusinessSettings struct {
@@ -67,7 +68,6 @@ func GetPublicBusinessInfo(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-
 	json.NewEncoder(w).Encode(info)
 }
 
@@ -90,7 +90,6 @@ func GetBusinessSettings(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-
 	json.NewEncoder(w).Encode(s)
 }
 
@@ -172,7 +171,7 @@ func UpdateBusinessSettings(w http.ResponseWriter, r *http.Request) {
 	}
 
 	setClauses := []string{}
-	args := []interface{}{}
+	args := []any{}
 	argIdx := 1
 
 	if req.BusinessName != nil {
@@ -231,12 +230,13 @@ func UpdateBusinessSettings(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	query := "UPDATE business_settings SET "
+	var query strings.Builder
+	query.WriteString("UPDATE business_settings SET ")
 	for i, clause := range setClauses {
 		if i > 0 {
-			query += ", "
+			query.WriteString(", ")
 		}
-		query += clause
+		query.WriteString(clause)
 	}
 
 	tx, err := db.Conn.Begin(r.Context())
@@ -247,7 +247,7 @@ func UpdateBusinessSettings(w http.ResponseWriter, r *http.Request) {
 	}
 	defer tx.Rollback(r.Context())
 
-	_, err = tx.Exec(r.Context(), query, args...)
+	_, err = tx.Exec(r.Context(), query.String(), args...)
 	if err != nil {
 		log.Printf("Failed to update business settings: %v", err)
 		http.Error(w, "Failed to update settings", http.StatusInternalServerError)
diff --git a/backend/handlers/admin/settings_test.go b/backend/handlers/admin/settings_test.go
index 25608cb..041faea 100644
--- a/backend/handlers/admin/settings_test.go
+++ b/backend/handlers/admin/settings_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package admin
 
diff --git a/backend/handlers/admin/test_helpers.go b/backend/handlers/admin/test_helpers.go
index 6ccc100..1259c1f 100644
--- a/backend/handlers/admin/test_helpers.go
+++ b/backend/handlers/admin/test_helpers.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package admin
 
diff --git a/backend/handlers/admin/testmain_test.go b/backend/handlers/admin/testmain_test.go
index 038c45d..8b4dd53 100644
--- a/backend/handlers/admin/testmain_test.go
+++ b/backend/handlers/admin/testmain_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package admin
 
diff --git a/backend/handlers/admin/today_test.go b/backend/handlers/admin/today_test.go
index 4548304..d6108f4 100644
--- a/backend/handlers/admin/today_test.go
+++ b/backend/handlers/admin/today_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package admin
 
@@ -24,10 +23,10 @@ import (
 	"time"
 
 	"crussell/clock"
-	"crussell/testutils"
 	"crussell/handlers/notifications"
 	"crussell/handlers/today"
 	"crussell/mw"
+	"crussell/testutils"
 )
 
 // TestAdminToday_CurrentNext verifies that an admin can retrieve the currently
diff --git a/backend/handlers/admin/update_booking_services_test.go b/backend/handlers/admin/update_booking_services_test.go
index ae5eaee..40dc350 100644
--- a/backend/handlers/admin/update_booking_services_test.go
+++ b/backend/handlers/admin/update_booking_services_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package admin
 
@@ -22,8 +21,8 @@ import (
 
 	"crussell/clock"
 	"crussell/db"
-	"crussell/testutils"
 	"crussell/handlers/bookings"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 )
 
@@ -80,7 +79,6 @@ func createSecondService(t *testing.T, tx db.Querier, ctx context.Context, name
 func TestAdminBookings_UpdateServices_ReplaceServices(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -129,7 +127,6 @@ func TestAdminBookings_UpdateServices_ReplaceServices(t *testing.T) {
 func TestAdminBookings_UpdateServices_AddService(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -175,7 +172,6 @@ func TestAdminBookings_UpdateServices_AddService(t *testing.T) {
 func TestAdminBookings_UpdateServices_RemoveService(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -233,7 +229,6 @@ func TestAdminBookings_UpdateServices_RemoveService(t *testing.T) {
 func TestAdminBookings_UpdateServices_WithPriceOverride(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -286,7 +281,6 @@ func TestAdminBookings_UpdateServices_WithPriceOverride(t *testing.T) {
 func TestAdminBookings_UpdateServices_WithDurationOverride(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -339,7 +333,6 @@ func TestAdminBookings_UpdateServices_WithDurationOverride(t *testing.T) {
 func TestAdminBookings_UpdateServices_WithBothOverrides(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -393,7 +386,6 @@ func TestAdminBookings_UpdateServices_WithBothOverrides(t *testing.T) {
 func TestAdminBookings_UpdateServices_UpdateNotes(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -438,7 +430,6 @@ func TestAdminBookings_UpdateServices_UpdateNotes(t *testing.T) {
 func TestAdminBookings_UpdateServices_MultipleOverrides(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -881,7 +872,6 @@ func TestAdminBookings_UpdateServices_WeCancelledBookingRejected(t *testing.T) {
 func TestAdminBookings_UpdateServices_OverlapWithNextBooking(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -927,7 +917,6 @@ func TestAdminBookings_UpdateServices_OverlapWithNextBooking(t *testing.T) {
 func TestAdminBookings_UpdateServices_NoOverlapSucceeds(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -972,7 +961,6 @@ func TestAdminBookings_UpdateServices_NoOverlapSucceeds(t *testing.T) {
 func TestAdminBookings_UpdateServices_NoNextBookingSucceeds(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -1014,7 +1002,6 @@ func TestAdminBookings_UpdateServices_NoNextBookingSucceeds(t *testing.T) {
 func TestAdminBookings_UpdateServices_ResponseShape(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -1082,7 +1069,6 @@ func TestAdminBookings_UpdateServices_ResponseShape(t *testing.T) {
 func TestAdminBookings_UpdateServices_PendingBooking(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -1117,7 +1103,6 @@ func TestAdminBookings_UpdateServices_PendingBooking(t *testing.T) {
 func TestAdminBookings_UpdateServices_InProgressBooking(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -1152,7 +1137,6 @@ func TestAdminBookings_UpdateServices_InProgressBooking(t *testing.T) {
 func TestAdminBookings_UpdateServices_ClearNotes(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	_, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
diff --git a/backend/handlers/admin/users_test.go b/backend/handlers/admin/users_test.go
index 73bc1a2..a14ccbb 100644
--- a/backend/handlers/admin/users_test.go
+++ b/backend/handlers/admin/users_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package admin
 
@@ -21,9 +20,9 @@ import (
 	"testing"
 	"time"
 
-	"crussell/testutils"
 	"crussell/handlers/user"
 	"crussell/mw"
+	"crussell/testutils"
 )
 
 // TestAdminUsers_List verifies that an admin can list all users in the
diff --git a/backend/handlers/auth/auth_test.go b/backend/handlers/auth/auth_test.go
index ca827ce..4803a7f 100644
--- a/backend/handlers/auth/auth_test.go
+++ b/backend/handlers/auth/auth_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package auth
 
@@ -357,7 +356,6 @@ func TestLogin_Success(t *testing.T) {
 	}
 	defer fixtures.DeleteUser(tx, userID)
 
-
 	body := LoginRequest{
 		Email:    "user@test.com",
 		Password: "testpassword123",
@@ -1396,7 +1394,6 @@ func TestLoginResponse_IncludesJTI(t *testing.T) {
 	}
 	defer fixtures.DeleteUser(tx, userID)
 
-
 	body := LoginRequest{
 		Email:    "jti-test@test.com",
 		Password: "testpassword123",
@@ -1599,7 +1596,6 @@ func TestLogin_AccountLockout_ResetsOnSuccess(t *testing.T) {
 		t.Fatalf("failed to set failed_attempts: %v", err)
 	}
 
-
 	body := LoginRequest{
 		Email:    "lockout-reset@test.com",
 		Password: "testpassword123",
@@ -1764,7 +1760,6 @@ func TestLogin_ResponseIncludesRefreshToken(t *testing.T) {
 	}
 	defer fixtures.DeleteUser(tx, userID)
 
-
 	body := LoginRequest{
 		Email:    "refresh-check@test.com",
 		Password: "testpassword123",
@@ -1933,9 +1928,9 @@ func TestCleanupStaleLoginEntries_Mixed(t *testing.T) {
 	loginStateMu.Lock()
 	saved := loginInProgress
 	loginInProgress = map[string]time.Time{
-		"stale-user":   clock.Now().Add(-60 * time.Second),
-		"recent-user":  clock.Now().Add(-5 * time.Second),
-		"borderline":   clock.Now().Add(-29 * time.Second), // Just under 30s threshold
+		"stale-user":  clock.Now().Add(-60 * time.Second),
+		"recent-user": clock.Now().Add(-5 * time.Second),
+		"borderline":  clock.Now().Add(-29 * time.Second), // Just under 30s threshold
 	}
 	loginStateMu.Unlock()
 	defer func() {
diff --git a/backend/handlers/auth/testmain_test.go b/backend/handlers/auth/testmain_test.go
index 93bb8bc..1f2f6d8 100644
--- a/backend/handlers/auth/testmain_test.go
+++ b/backend/handlers/auth/testmain_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package auth
 
diff --git a/backend/handlers/bookings/admin_cancel_reservation_test.go b/backend/handlers/bookings/admin_cancel_reservation_test.go
index 052939a..05af69a 100644
--- a/backend/handlers/bookings/admin_cancel_reservation_test.go
+++ b/backend/handlers/bookings/admin_cancel_reservation_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package bookings
 
diff --git a/backend/handlers/bookings/admin_reserve_test.go b/backend/handlers/bookings/admin_reserve_test.go
index e24b774..a7de0bf 100644
--- a/backend/handlers/bookings/admin_reserve_test.go
+++ b/backend/handlers/bookings/admin_reserve_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package bookings
 
@@ -20,8 +19,8 @@ import (
 	"time"
 
 	"crussell/clock"
-	"crussell/testutils"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 
 	"github.com/go-chi/chi/v5"
@@ -68,7 +67,6 @@ func TestAdminReserveSlot_WalkIn_Success(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-
 	adminID, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create admin: %v", err)
@@ -126,7 +124,6 @@ func TestAdminReserveSlot_CallIn_Success(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-
 	adminID, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create admin: %v", err)
@@ -202,8 +199,6 @@ func TestAdminReserveSlot_WalkIn_MissingDuration(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	adminID, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create admin: %v", err)
@@ -241,8 +236,6 @@ func TestAdminReserveSlot_CallIn_MissingServices(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	adminID, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create admin: %v", err)
@@ -283,8 +276,6 @@ func TestAdminReserveSlot_InvalidReservationType(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	adminID, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create admin: %v", err)
@@ -321,8 +312,6 @@ func TestAdminReserveSlot_SlotOverlap(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	// Create test admin user (for the booking)
 	adminID, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -394,8 +383,6 @@ func TestAdminReserveSlot_ReplacesExisting(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	adminID, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create admin: %v", err)
@@ -483,8 +470,6 @@ func TestAdminReserveSlot_WalkIn_PastStart(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	adminID, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create admin: %v", err)
diff --git a/backend/handlers/bookings/bookings.go b/backend/handlers/bookings/bookings.go
index 6642af4..7410503 100644
--- a/backend/handlers/bookings/bookings.go
+++ b/backend/handlers/bookings/bookings.go
@@ -2,8 +2,8 @@ package bookings
 
 import (
 	"context"
-	"crussell/db"
 	"crussell/clock"
+	"crussell/db"
 	"crussell/handlers/notifications"
 	"crussell/handlers/payments"
 	"crussell/handlers/scheduling"
@@ -254,20 +254,20 @@ type AdminBookingSummary struct {
 }
 
 type UserSummary struct {
-	ID               string  `json:"id"`
-	FirstName        string  `json:"first_name"`
-	LastName         string  `json:"last_name"`
-	FullName         string  `json:"full_name"`
-	Email            *string `json:"email,omitempty"`
-	Phone            *string `json:"phone,omitempty"`
-	ProfilePicURL    *string `json:"profile_pic_url,omitempty"`
-	DateOfBirth      *string `json:"date_of_birth,omitempty"`
-	AccountRole      string  `json:"account_role"`
-	LoyaltyStamps    *int    `json:"loyalty_stamps,omitempty"`
-	ReferralCode     *string `json:"referral_code,omitempty"`
-	ReferralCodeUses *int    `json:"referral_code_uses,omitempty"`
-	CreatedAt        string  `json:"created_at"`
-	Notes            *string `json:"notes,omitempty" validate:"omitempty,max=1000000"`
+	ID                string  `json:"id"`
+	FirstName         string  `json:"first_name"`
+	LastName          string  `json:"last_name"`
+	FullName          string  `json:"full_name"`
+	Email             *string `json:"email,omitempty"`
+	Phone             *string `json:"phone,omitempty"`
+	ProfilePicURL     *string `json:"profile_pic_url,omitempty"`
+	DateOfBirth       *string `json:"date_of_birth,omitempty"`
+	AccountRole       string  `json:"account_role"`
+	LoyaltyStamps     *int    `json:"loyalty_stamps,omitempty"`
+	ReferralCode      *string `json:"referral_code,omitempty"`
+	ReferralCodeUses  *int    `json:"referral_code_uses,omitempty"`
+	CreatedAt         string  `json:"created_at"`
+	Notes             *string `json:"notes,omitempty" validate:"omitempty,max=1000000"`
 	PreviousFirstName *string `json:"previous_first_name,omitempty"`
 	PreviousLastName  *string `json:"previous_last_name,omitempty"`
 }
@@ -387,7 +387,7 @@ func GetAllUserBookingsHandler(w http.ResponseWriter, r *http.Request) {
 
 	// Build WHERE conditions shared between count and data queries.
 	whereClause := " WHERE b.user_id = $1"
-	whereArgs := []interface{}{userID}
+	whereArgs := []any{userID}
 	paramCount := 2
 
 	if req.Status != nil {
@@ -447,7 +447,7 @@ func GetAllUserBookingsHandler(w http.ResponseWriter, r *http.Request) {
             WHERE booking_id = b.id
         ) pt ON true` + whereClause
 
-	dataArgs := make([]interface{}, len(whereArgs))
+	dataArgs := make([]any, len(whereArgs))
 	copy(dataArgs, whereArgs)
 	dataParamCount := paramCount
 
@@ -683,7 +683,7 @@ func GetAllAdminBookingsHandler(w http.ResponseWriter, r *http.Request) {
         ) pre_pay ON true
     `
 
-	var args []interface{}
+	var args []any
 	paramCount := 1
 
 	addWhereClause := func(condition string) {
@@ -750,7 +750,7 @@ func GetAllAdminBookingsHandler(w http.ResponseWriter, r *http.Request) {
 	var total int
 	{
 		countWhere := ""
-		var countArgs []interface{}
+		var countArgs []any
 		cp := 1
 		addCountWhere := func(cond string) {
 			if cp == 1 {
@@ -954,7 +954,7 @@ func GetAllBookingsByUserHandler(w http.ResponseWriter, r *http.Request) {
 		FROM bookings b
 		WHERE b.user_id = $1
 	`
-	var args []interface{}
+	var args []any
 	args = append(args, userID)
 	paramCount := 2
 
@@ -1793,7 +1793,7 @@ func SearchAdminBookingsHandler(w http.ResponseWriter, r *http.Request) {
                 WHERE bcs.booking_id = b.id AND cs.name ILIKE $1 ESCAPE '\'
             )
     `
-	var args []interface{}
+	var args []any
 	args = append(args, searchPattern)
 	paramCount := 2
 
@@ -2639,9 +2639,9 @@ func ProgressBookingHandler(w http.ResponseWriter, r *http.Request) {
 		if currentStatus == "completed" {
 			log.Printf("Booking %s is already completed — skipping duplicate completion", bookingID)
 		} else {
-		// Collect patch test IDs first so the rows are consumed before INSERT operations.
-		var patchTestIDs []string
-		ptRows, err := tx.Query(r.Context(), `
+			// Collect patch test IDs first so the rows are consumed before INSERT operations.
+			var patchTestIDs []string
+			ptRows, err := tx.Query(r.Context(), `
 			SELECT DISTINCT pt.id
 			FROM patch_tests pt
 			JOIN booking_services bs ON bs.booking_id = $1
@@ -2649,42 +2649,42 @@ func ProgressBookingHandler(w http.ResponseWriter, r *http.Request) {
 				SELECT pt_inner.id FROM patch_tests pt_inner WHERE bs.service_id = ANY(pt_inner.service_ids)
 			)
 		`, bookingID)
-		if err != nil {
-			log.Printf("Failed to fetch patch tests for booking %s: %v", bookingID, err)
-		} else {
-			for ptRows.Next() {
-				var ptID string
-				if err := ptRows.Scan(&ptID); err == nil {
-					patchTestIDs = append(patchTestIDs, ptID)
+			if err != nil {
+				log.Printf("Failed to fetch patch tests for booking %s: %v", bookingID, err)
+			} else {
+				for ptRows.Next() {
+					var ptID string
+					if err := ptRows.Scan(&ptID); err == nil {
+						patchTestIDs = append(patchTestIDs, ptID)
+					}
 				}
+				ptRows.Close()
 			}
-			ptRows.Close()
-		}
-		for _, ptID := range patchTestIDs {
-			if _, err := tx.Exec(r.Context(), `
+			for _, ptID := range patchTestIDs {
+				if _, err := tx.Exec(r.Context(), `
 				INSERT INTO user_patch_tests (user_id, patch_test_id, tested_at)
 				VALUES ($1, $2, NOW())
 				ON CONFLICT (user_id, patch_test_id) DO UPDATE SET tested_at = NOW()
 			`, booking.User.ID, ptID); err != nil {
-				log.Printf("Failed to update patch test validity for user %s, patch test %s: %v", booking.User.ID, ptID, err)
+					log.Printf("Failed to update patch test validity for user %s, patch test %s: %v", booking.User.ID, ptID, err)
+				}
 			}
-		}
 
-		var bookingTotal float64
-		if err := tx.QueryRow(r.Context(), `
+			var bookingTotal float64
+			if err := tx.QueryRow(r.Context(), `
 			SELECT total_amount FROM bookings WHERE id = $1
 		`, bookingID).Scan(&bookingTotal); err != nil {
-			log.Printf("Failed to calculate booking total for %s: %v", bookingID, err)
-		}
+				log.Printf("Failed to calculate booking total for %s: %v", bookingID, err)
+			}
 
-		// Don't award a stamp if this booking already used a loyalty redemption
-		// (take or receive, never both).
-		var loyaltyAppliedOnThisBooking bool
-		tx.QueryRow(r.Context(), `SELECT EXISTS(SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'loyalty')`, bookingID).Scan(&loyaltyAppliedOnThisBooking)
+			// Don't award a stamp if this booking already used a loyalty redemption
+			// (take or receive, never both).
+			var loyaltyAppliedOnThisBooking bool
+			tx.QueryRow(r.Context(), `SELECT EXISTS(SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'loyalty')`, bookingID).Scan(&loyaltyAppliedOnThisBooking)
 
-		var newStampCount int
-		if bookingTotal > 0 && !loyaltyAppliedOnThisBooking {
-			if err := tx.QueryRow(r.Context(), `
+			var newStampCount int
+			if bookingTotal > 0 && !loyaltyAppliedOnThisBooking {
+				if err := tx.QueryRow(r.Context(), `
 				UPDATE users
 				SET loyalty_stamps = loyalty_stamps + 1
 				WHERE id = $1
@@ -2697,108 +2697,108 @@ func ProgressBookingHandler(w http.ResponseWriter, r *http.Request) {
 				)
 				RETURNING loyalty_stamps
 			`, booking.User.ID, bookingID).Scan(&newStampCount); err != nil {
-				if !errors.Is(err, pgx.ErrNoRows) {
-					log.Printf("Failed to add loyalty stamp for booking %s: %v", bookingID, err)
+					if !errors.Is(err, pgx.ErrNoRows) {
+						log.Printf("Failed to add loyalty stamp for booking %s: %v", bookingID, err)
+					}
 				}
 			}
-		}
 
-		// Create pending redemption when stamps reach LoyaltyStampCost
-		if newStampCount == payments.LoyaltyStampCost {
-			_, err = tx.Exec(r.Context(), `
+			// Create pending redemption when stamps reach LoyaltyStampCost
+			if newStampCount == payments.LoyaltyStampCost {
+				_, err = tx.Exec(r.Context(), `
 				INSERT INTO loyalty_redemptions (user_id, stamps_redeemed, status, redeemed_at)
 				VALUES ($1, $2, 'pending', NOW())
 			`, booking.User.ID, payments.LoyaltyStampCost)
-			if err != nil {
-				log.Printf("Failed to create loyalty redemption for user %s: %v", booking.User.ID, err)
+				if err != nil {
+					log.Printf("Failed to create loyalty redemption for user %s: %v", booking.User.ID, err)
+				}
 			}
-		}
 
-		// Skip time-based campaign if already applied at payment time
-		var timeBasedApplied bool
-		tx.QueryRow(r.Context(), `SELECT EXISTS(SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'campaign' AND campaign_type = 'time_based')`, bookingID).Scan(&timeBasedApplied)
-		if bookingTotal > 0 && !timeBasedApplied {
-			var campaignID string
-			var campaignPercent float64
-			if err := tx.QueryRow(r.Context(), `
+			// Skip time-based campaign if already applied at payment time
+			var timeBasedApplied bool
+			tx.QueryRow(r.Context(), `SELECT EXISTS(SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'campaign' AND campaign_type = 'time_based')`, bookingID).Scan(&timeBasedApplied)
+			if bookingTotal > 0 && !timeBasedApplied {
+				var campaignID string
+				var campaignPercent float64
+				if err := tx.QueryRow(r.Context(), `
 				SELECT id, discount_percent FROM discount_campaigns
 				WHERE status = 'active' AND campaign_type = 'time_based'
 				AND start_date <= NOW() AND end_date >= NOW()
 				AND (max_redemptions IS NULL OR times_redeemed < max_redemptions)
 				ORDER BY discount_percent DESC LIMIT 1
 			`).Scan(&campaignID, &campaignPercent); err == nil && campaignID != "" {
-				discountAmount := roundTo2(bookingTotal * campaignPercent / 100)
+					discountAmount := roundTo2(bookingTotal * campaignPercent / 100)
 
-				if _, err := tx.Exec(r.Context(), `
+					if _, err := tx.Exec(r.Context(), `
 					INSERT INTO booking_discounts (booking_id, user_id, discount_source, source_id, campaign_type, milestone_type, discount_percent, original_total, discount_amount)
 					VALUES ($1, $2, 'campaign', $3, 'time_based', NULL, $4, $5, $6)
 				`, bookingID, booking.User.ID, campaignID, campaignPercent, bookingTotal, discountAmount); err != nil {
-					log.Printf("ALERT: failed to insert booking discount: %v", err)
-				}
+						log.Printf("ALERT: failed to insert booking discount: %v", err)
+					}
 
-				if _, err := tx.Exec(r.Context(), `
+					if _, err := tx.Exec(r.Context(), `
 					INSERT INTO payments (booking_id, payment_type, payment_method, amount, status, created_by)
 					VALUES ($1, 'partial', 'discount', $2, 'completed', $3)
 				`, bookingID, discountAmount, booking.User.ID); err != nil {
-					log.Printf("ALERT: failed to insert payment record: %v", err)
-				}
+						log.Printf("ALERT: failed to insert payment record: %v", err)
+					}
 
-				if _, err := tx.Exec(r.Context(), `
+					if _, err := tx.Exec(r.Context(), `
 					UPDATE discount_campaigns SET times_redeemed = times_redeemed + 1 WHERE id = $1
 				`, campaignID); err != nil {
-					log.Printf("ALERT: failed to update discount campaign usage: %v", err)
+						log.Printf("ALERT: failed to update discount campaign usage: %v", err)
+					}
 				}
 			}
-		}
 
-		if bookingTotal > 0 {
-			var userBookingCount int
-			_ = tx.QueryRow(r.Context(), `SELECT COUNT(*) FROM bookings WHERE user_id = $1 AND status = 'completed'`, booking.User.ID).Scan(&userBookingCount)
+			if bookingTotal > 0 {
+				var userBookingCount int
+				_ = tx.QueryRow(r.Context(), `SELECT COUNT(*) FROM bookings WHERE user_id = $1 AND status = 'completed'`, booking.User.ID).Scan(&userBookingCount)
 
-			var milestoneCampaignID string
-			var milestonePercent float64
-			_ = tx.QueryRow(r.Context(), `
+				var milestoneCampaignID string
+				var milestonePercent float64
+				_ = tx.QueryRow(r.Context(), `
 				SELECT id, discount_percent FROM discount_campaigns
 				WHERE status = 'active' AND campaign_type = 'milestone' AND milestone_type = 'per_user_booking_count'
 				AND milestone_value = $1
 				AND NOT EXISTS (SELECT 1 FROM booking_discounts WHERE user_id = $2 AND source_id = discount_campaigns.id)
 			`, userBookingCount, booking.User.ID).Scan(&milestoneCampaignID, &milestonePercent)
 
-			if milestoneCampaignID != "" {
-				discountAmount := roundTo2(bookingTotal * milestonePercent / 100)
-				if _, err := tx.Exec(r.Context(), `
+				if milestoneCampaignID != "" {
+					discountAmount := roundTo2(bookingTotal * milestonePercent / 100)
+					if _, err := tx.Exec(r.Context(), `
 					INSERT INTO booking_discounts (booking_id, user_id, discount_source, source_id, campaign_type, milestone_type, discount_percent, original_total, discount_amount)
 					VALUES ($1, $2, 'campaign', $3, 'milestone', 'per_user_booking_count', $4, $5, $6)
 				`, bookingID, booking.User.ID, milestoneCampaignID, milestonePercent, bookingTotal, discountAmount); err != nil {
-					log.Printf("ALERT: failed to insert booking discount: %v", err)
-				}
-				if _, err := tx.Exec(r.Context(), `
+						log.Printf("ALERT: failed to insert booking discount: %v", err)
+					}
+					if _, err := tx.Exec(r.Context(), `
 					INSERT INTO payments (booking_id, payment_type, payment_method, amount, status, created_by)
 					VALUES ($1, 'partial', 'discount', $2, 'completed', $3)
 				`, bookingID, discountAmount, booking.User.ID); err != nil {
-					log.Printf("ALERT: failed to insert payment record: %v", err)
-				}
-				if _, err := tx.Exec(r.Context(), `
+						log.Printf("ALERT: failed to insert payment record: %v", err)
+					}
+					if _, err := tx.Exec(r.Context(), `
 					UPDATE discount_campaigns SET times_redeemed = times_redeemed + 1 WHERE id = $1
 				`, milestoneCampaignID); err != nil {
-					log.Printf("ALERT: failed to insert payment record: %v", err)
+						log.Printf("ALERT: failed to insert payment record: %v", err)
+					}
 				}
-			}
 
-			var globalMilestoneApplied bool
-			tx.QueryRow(r.Context(), `SELECT EXISTS(SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'campaign' AND campaign_type = 'milestone' AND milestone_type = 'global_booking_count')`, bookingID).Scan(&globalMilestoneApplied)
-			if !globalMilestoneApplied {
-				var globalCount int
-				_ = tx.QueryRow(r.Context(), `SELECT COUNT(*) FROM bookings WHERE status = 'completed'`).Scan(&globalCount)
+				var globalMilestoneApplied bool
+				tx.QueryRow(r.Context(), `SELECT EXISTS(SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'campaign' AND campaign_type = 'milestone' AND milestone_type = 'global_booking_count')`, bookingID).Scan(&globalMilestoneApplied)
+				if !globalMilestoneApplied {
+					var globalCount int
+					_ = tx.QueryRow(r.Context(), `SELECT COUNT(*) FROM bookings WHERE status = 'completed'`).Scan(&globalCount)
 
-				var hasInPersonPayment bool
-				tx.QueryRow(r.Context(), `
+					var hasInPersonPayment bool
+					tx.QueryRow(r.Context(), `
 					SELECT EXISTS(SELECT 1 FROM payments WHERE booking_id = $1 AND payment_method = 'in_person_card')`, bookingID).Scan(&hasInPersonPayment)
 
-				if hasInPersonPayment {
-					var globalCampaignID string
-					var globalPercent float64
-					_ = tx.QueryRow(r.Context(), `
+					if hasInPersonPayment {
+						var globalCampaignID string
+						var globalPercent float64
+						_ = tx.QueryRow(r.Context(), `
 						SELECT id, discount_percent FROM discount_campaigns
 						WHERE status = 'active' AND campaign_type = 'milestone' AND milestone_type = 'global_booking_count'
 						AND milestone_value <= $1
@@ -2806,126 +2806,126 @@ func ProgressBookingHandler(w http.ResponseWriter, r *http.Request) {
 						ORDER BY milestone_value DESC LIMIT 1
 					`, globalCount).Scan(&globalCampaignID, &globalPercent)
 
-					if globalCampaignID != "" {
-						discountAmount := roundTo2(bookingTotal * globalPercent / 100)
-						if _, err := tx.Exec(r.Context(), `
+						if globalCampaignID != "" {
+							discountAmount := roundTo2(bookingTotal * globalPercent / 100)
+							if _, err := tx.Exec(r.Context(), `
 							INSERT INTO booking_discounts (booking_id, user_id, discount_source, source_id, campaign_type, milestone_type, discount_percent, original_total, discount_amount)
 							VALUES ($1, $2, 'campaign', $3, 'milestone', 'global_booking_count', $4, $5, $6)
 						`, bookingID, booking.User.ID, globalCampaignID, globalPercent, bookingTotal, discountAmount); err != nil {
-							log.Printf("ALERT: failed to insert booking discount: %v", err)
-						}
-						if _, err := tx.Exec(r.Context(), `
+								log.Printf("ALERT: failed to insert booking discount: %v", err)
+							}
+							if _, err := tx.Exec(r.Context(), `
 							INSERT INTO payments (booking_id, payment_type, payment_method, amount, status, created_by)
 							VALUES ($1, 'partial', 'discount', $2, 'completed', $3)
 						`, bookingID, discountAmount, booking.User.ID); err != nil {
-							log.Printf("ALERT: failed to insert payment record: %v", err)
-						}
-						if _, err := tx.Exec(r.Context(), `
+								log.Printf("ALERT: failed to insert payment record: %v", err)
+							}
+							if _, err := tx.Exec(r.Context(), `
 							UPDATE discount_campaigns SET times_redeemed = times_redeemed + 1 WHERE id = $1
 						`, globalCampaignID); err != nil {
-							log.Printf("ALERT: failed to insert payment record: %v", err)
+								log.Printf("ALERT: failed to insert payment record: %v", err)
+							}
 						}
 					}
 				}
-			}
 
-			var firstVisitDate time.Time
-			_ = tx.QueryRow(r.Context(), `SELECT MIN(start_time) FROM bookings WHERE user_id = $1 AND status = 'completed'`, booking.User.ID).Scan(&firstVisitDate)
-			if !firstVisitDate.IsZero() {
-				annRows, err := tx.Query(r.Context(), `
+				var firstVisitDate time.Time
+				_ = tx.QueryRow(r.Context(), `SELECT MIN(start_time) FROM bookings WHERE user_id = $1 AND status = 'completed'`, booking.User.ID).Scan(&firstVisitDate)
+				if !firstVisitDate.IsZero() {
+					annRows, err := tx.Query(r.Context(), `
 					SELECT id, discount_percent, milestone_value, milestone_unit FROM discount_campaigns
 					WHERE status = 'active' AND campaign_type = 'milestone' AND milestone_type = 'anniversary'
 					AND NOT EXISTS (SELECT 1 FROM booking_discounts WHERE user_id = $1 AND source_id = discount_campaigns.id AND milestone_type = 'anniversary')
 				`, booking.User.ID)
-				if err == nil {
-					// Collect anniversary campaigns first to avoid interleaving rows with writes.
-					type annCampaign struct {
-						id    string
-						pct   float64
-						value int
-						unit  string
-					}
-					var campaigns []annCampaign
-					for annRows.Next() {
-						var c annCampaign
-						if annRows.Scan(&c.id, &c.pct, &c.value, &c.unit) == nil {
-							campaigns = append(campaigns, c)
+					if err == nil {
+						// Collect anniversary campaigns first to avoid interleaving rows with writes.
+						type annCampaign struct {
+							id    string
+							pct   float64
+							value int
+							unit  string
 						}
-					}
-					annRows.Close()
+						var campaigns []annCampaign
+						for annRows.Next() {
+							var c annCampaign
+							if annRows.Scan(&c.id, &c.pct, &c.value, &c.unit) == nil {
+								campaigns = append(campaigns, c)
+							}
+						}
+						annRows.Close()
 
-					// Sort by milestone_value descending so we apply the longest anniversary only
-					sort.Slice(campaigns, func(i, j int) bool {
-						return campaigns[i].value > campaigns[j].value
-					})
-					for _, c := range campaigns {
-						var matches bool
-						elapsed := time.Since(firstVisitDate)
-						switch c.unit {
-						case "months":
-							months := int(elapsed.Hours() / (30 * 24))
-							matches = months >= c.value
-						case "years":
-							years := int(elapsed.Hours() / (365.25 * 24))
-							matches = years >= c.value
-						}
-						if matches {
-							discountAmount := roundTo2(bookingTotal * c.pct / 100)
-							if _, err := tx.Exec(r.Context(), `
+						// Sort by milestone_value descending so we apply the longest anniversary only
+						sort.Slice(campaigns, func(i, j int) bool {
+							return campaigns[i].value > campaigns[j].value
+						})
+						for _, c := range campaigns {
+							var matches bool
+							elapsed := time.Since(firstVisitDate)
+							switch c.unit {
+							case "months":
+								months := int(elapsed.Hours() / (30 * 24))
+								matches = months >= c.value
+							case "years":
+								years := int(elapsed.Hours() / (365.25 * 24))
+								matches = years >= c.value
+							}
+							if matches {
+								discountAmount := roundTo2(bookingTotal * c.pct / 100)
+								if _, err := tx.Exec(r.Context(), `
 								INSERT INTO booking_discounts (booking_id, user_id, discount_source, source_id, campaign_type, milestone_type, discount_percent, original_total, discount_amount)
 								VALUES ($1, $2, 'campaign', $3, 'milestone', 'anniversary', $4, $5, $6)
 							`, bookingID, booking.User.ID, c.id, c.pct, bookingTotal, discountAmount); err != nil {
-								log.Printf("ALERT: failed to insert booking discount: %v", err)
-							}
-							if _, err := tx.Exec(r.Context(), `
+									log.Printf("ALERT: failed to insert booking discount: %v", err)
+								}
+								if _, err := tx.Exec(r.Context(), `
 								INSERT INTO payments (booking_id, payment_type, payment_method, amount, status, created_by)
 								VALUES ($1, 'partial', 'discount', $2, 'completed', $3)
 							`, bookingID, discountAmount, booking.User.ID); err != nil {
-								log.Printf("ALERT: failed to insert payment record: %v", err)
-							}
-							if _, err := tx.Exec(r.Context(), `
+									log.Printf("ALERT: failed to insert payment record: %v", err)
+								}
+								if _, err := tx.Exec(r.Context(), `
 								UPDATE discount_campaigns SET times_redeemed = times_redeemed + 1 WHERE id = $1
 							`, c.id); err != nil {
-								log.Printf("ALERT: failed to insert payment record: %v", err)
+									log.Printf("ALERT: failed to insert payment record: %v", err)
+								}
+								break // apply longest matching only
 							}
-							break   // apply longest matching only
 						}
 					}
 				}
 			}
-		}
 
-		var paymentExists bool
-		if err := tx.QueryRow(r.Context(), `SELECT EXISTS(SELECT 1 FROM payments WHERE booking_id = $1)`, bookingID).Scan(&paymentExists); err == nil && paymentExists {
-			var newDepositsRequired int
-			if err := tx.QueryRow(r.Context(), `
+			var paymentExists bool
+			if err := tx.QueryRow(r.Context(), `SELECT EXISTS(SELECT 1 FROM payments WHERE booking_id = $1)`, bookingID).Scan(&paymentExists); err == nil && paymentExists {
+				var newDepositsRequired int
+				if err := tx.QueryRow(r.Context(), `
 				UPDATE users SET deposits_required = GREATEST(0, deposits_required - 1)
 				WHERE id = $1
 				RETURNING deposits_required
 			`, booking.User.ID).Scan(&newDepositsRequired); err != nil {
-				log.Printf("ALERT: failed to update deposits_required: %v", err)
-			} else if newDepositsRequired == 0 {
-				// After 3 paid bookings, forget no-shows so the counter resets.
-				if _, err := tx.Exec(r.Context(), `
+					log.Printf("ALERT: failed to update deposits_required: %v", err)
+				} else if newDepositsRequired == 0 {
+					// After 3 paid bookings, forget no-shows so the counter resets.
+					if _, err := tx.Exec(r.Context(), `
 					INSERT INTO forgiven_no_shows (booking_id)
 					SELECT id FROM bookings
 					WHERE user_id = $1 AND status = 'no_show'
 					  AND start_time >= NOW() - INTERVAL '6 months'
 					  AND NOT EXISTS (SELECT 1 FROM forgiven_no_shows WHERE booking_id = bookings.id)
 				`, booking.User.ID); err != nil {
-					log.Printf("ALERT: failed to auto-forgive no-shows: %v", err)
+						log.Printf("ALERT: failed to auto-forgive no-shows: %v", err)
+					}
 				}
 			}
-		}
-		// Consume unconsumed name_history entries — this booking is the "first post-name-change
-		// booking" that completes. After this, we no longer show "formerly" on displays.
-		if _, err := tx.Exec(r.Context(), `
+			// Consume unconsumed name_history entries — this booking is the "first post-name-change
+			// booking" that completes. After this, we no longer show "formerly" on displays.
+			if _, err := tx.Exec(r.Context(), `
 			UPDATE name_history SET booking_id = $1
 			WHERE user_id = $2 AND booking_id IS NULL
 		`, bookingID, booking.User.ID); err != nil {
-			log.Printf("Failed to consume name_history for user %s: %v", booking.User.ID, err)
-		}
-	}	// close the else from alreadyCompleted check
+				log.Printf("Failed to consume name_history for user %s: %v", booking.User.ID, err)
+			}
+		} // close the else from alreadyCompleted check
 	}
 
 	if err := tx.Commit(r.Context()); err != nil {
@@ -3288,7 +3288,7 @@ func DeleteBookingHandler(w http.ResponseWriter, r *http.Request) {
 			}
 		}
 
-		resp := map[string]interface{}{
+		resp := map[string]any{
 			"message": "Booking cancelled successfully",
 			"id":      bookingID,
 			"status":  req.Reason,
@@ -3336,7 +3336,7 @@ func DeleteBookingHandler(w http.ResponseWriter, r *http.Request) {
 
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(http.StatusOK)
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"message": "Booking deleted successfully",
 		"id":      bookingID,
 	})
diff --git a/backend/handlers/bookings/bookings_test.go b/backend/handlers/bookings/bookings_test.go
index 44c034d..7056df0 100644
--- a/backend/handlers/bookings/bookings_test.go
+++ b/backend/handlers/bookings/bookings_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package bookings
 
@@ -30,10 +29,10 @@ import (
 
 	"crussell/clock"
 	"crussell/db"
-	"crussell/testutils"
 	"crussell/handlers/user"
 	"crussell/internal/validators"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 	"crussell/testutils/jwt"
 
@@ -217,7 +216,6 @@ func TestBookings_Create(t *testing.T) {
 	ctx, tx := testutils.SetupTestTx(t)
 
 	// Seed working hours for booking tests
-	
 
 	// Create test user and service
 	userID, err := fixtures.CreateTestUser(tx)
@@ -1099,10 +1097,8 @@ func TestBookings_Delete_NotFound(t *testing.T) {
 // - Cancellation < 24 hours before appointment: treated as no-show (deposits = 3)
 // - Cancellation >= 24 hours before appointment: treated as late_cancellation
 func TestBookings_Delete_NoShow24hThreshold(t *testing.T) {
-	
-	ctx, tx := testutils.SetupTestTx(t)
 
-	
+	ctx, tx := testutils.SetupTestTx(t)
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -1162,10 +1158,8 @@ func TestBookings_Delete_NoShow24hThreshold(t *testing.T) {
 
 // TestBookings_Delete_NoShow_WithForgiveness tests that admin can forgive a no-show
 func TestBookings_Delete_NoShow_WithForgiveness(t *testing.T) {
-	
-	ctx, tx := testutils.SetupTestTx(t)
 
-	
+	ctx, tx := testutils.SetupTestTx(t)
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -1459,7 +1453,6 @@ func TestBookings_Create_MinimumAdvance(t *testing.T) {
 	ctx, tx := testutils.SetupTestTx(t)
 
 	// Seed working hours for booking tests
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -1513,7 +1506,6 @@ func TestBookings_Create_WithNotes_StatusPending(t *testing.T) {
 	ctx, tx := testutils.SetupTestTx(t)
 
 	// Seed working hours
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -1567,7 +1559,6 @@ func TestBookings_Create_WithoutNotes_StatusConfirmed(t *testing.T) {
 	ctx, tx := testutils.SetupTestTx(t)
 
 	// Seed working hours
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -1615,7 +1606,6 @@ func TestBookings_Create_Within1Hour_ShouldFail(t *testing.T) {
 	ctx, tx := testutils.SetupTestTx(t)
 
 	// Seed working hours
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -1654,7 +1644,6 @@ func TestBookings_Create_MultipleServices(t *testing.T) {
 	ctx, tx := testutils.SetupTestTx(t)
 
 	// Seed working hours for booking tests
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -1715,10 +1704,8 @@ func TestBookings_Create_MultipleServices(t *testing.T) {
 // booking is cancelled within 24 hours (with no forgiveness), the system
 // overrides the cancellation to "no_show" and deposits_required stays 0.
 func TestDeleteBooking_NoShowUnder24h_SetsDepositsTo3(t *testing.T) {
-	
-	ctx, tx := testutils.SetupTestTx(t)
 
-	
+	ctx, tx := testutils.SetupTestTx(t)
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -1798,10 +1785,8 @@ func TestDeleteBooking_NoShowUnder24h_SetsDepositsTo3(t *testing.T) {
 // cancelled with more than 24 hours notice (client_cancelled), no deposit penalty
 // is applied and deposits_required remains 0.
 func TestDeleteBooking_CancelOver24h_NoDepositPenalty(t *testing.T) {
-	
-	ctx, tx := testutils.SetupTestTx(t)
 
-	
+	ctx, tx := testutils.SetupTestTx(t)
 
 	// Create test user with deposits_required = 0
 	userID, err := fixtures.CreateTestUser(tx)
@@ -1883,10 +1868,8 @@ func TestDeleteBooking_CancelOver24h_NoDepositPenalty(t *testing.T) {
 // booking is cancelled within 24 hours with forgiveness, the system overrides to
 // "client_cancelled" (no no-show penalty).
 func TestDeleteBooking_NoShowWithForgiveness_NoPenalty(t *testing.T) {
-	
-	ctx, tx := testutils.SetupTestTx(t)
 
-	
+	ctx, tx := testutils.SetupTestTx(t)
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -1968,10 +1951,8 @@ func TestDeleteBooking_NoShowWithForgiveness_NoPenalty(t *testing.T) {
 // no-show, the deposits_required stays at 3 (not 6). The handler sets deposits to 3
 // on the first no-show and doesn't increment on subsequent no-shows.
 func TestDeleteBooking_SecondNoShow_StaysAt3(t *testing.T) {
-	
-	ctx, tx := testutils.SetupTestTx(t)
 
-	
+	ctx, tx := testutils.SetupTestTx(t)
 
 	// Create test user with deposits_required = 0
 	userID, err := fixtures.CreateTestUser(tx)
@@ -2858,8 +2839,6 @@ func TestCreateEditRequest_WithTimeChange(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -3274,8 +3253,6 @@ func TestAdminApproveEditRequest_DeletesTimeBlocker(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -3373,8 +3350,6 @@ func TestAdminRejectEditRequest_DeletesTimeBlocker(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -3471,8 +3446,6 @@ func TestDeleteEditRequest_DeletesTimeBlocker(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -3552,8 +3525,6 @@ func TestAdminApproveEditRequest_TimeBlockerOverlap(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -3765,8 +3736,6 @@ func TestBookings_Create_PatchTestRequired_NoRecord(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	// Create user and service with patch test requirement
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -3815,8 +3784,6 @@ func TestBookings_Create_PatchTestRequired_WithinNoticePeriod(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -3872,8 +3839,6 @@ func TestBookings_Create_PatchTestRequired_Expired(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -3926,8 +3891,6 @@ func TestBookings_Create_PatchTestRequired_ValidRecord(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -3992,8 +3955,6 @@ func TestBookings_Create_DepositRequired_WithinAdvanceWindow(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -4040,8 +4001,6 @@ func TestBookings_Create_DepositRequired_After48Hours(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -4092,10 +4051,8 @@ func TestBookings_Create_DepositRequired_After48Hours(t *testing.T) {
 // TestBookings_Create_NoDepositRequired_Within48Hours verifies that a user with deposits_required=0
 // can book at any time (no 48h restriction).
 func TestBookings_Create_NoDepositRequired_Within48Hours(t *testing.T) {
-	
-	ctx, tx := testutils.SetupTestTx(t)
 
-	
+	ctx, tx := testutils.SetupTestTx(t)
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -4143,8 +4100,6 @@ func TestBookings_Create_DepositSnapshot(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -4214,8 +4169,6 @@ func TestBookings_Create_DepositRequired_OneActiveBookingLimit(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -4276,8 +4229,6 @@ func TestBookings_Get_DepositFieldsReturned(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -4356,7 +4307,6 @@ func TestBookings_Get_DepositFieldsReturned(t *testing.T) {
 func TestBookings_Get_ServicesReturned(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -4427,7 +4377,6 @@ func TestBookings_Get_ServicesReturned(t *testing.T) {
 func TestBookings_Get_CustomServicesReturned(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -4511,7 +4460,6 @@ func TestBookings_Get_CustomServicesReturned(t *testing.T) {
 func TestBookings_Get_EmptyServices(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -4562,8 +4510,6 @@ func TestBookings_Edit_ClosedDay_UserBlocked(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -4651,8 +4597,6 @@ func TestBookings_Edit_OpenDay_UserAllowed(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -4739,8 +4683,6 @@ func TestBookings_Create_OverlappingBlocker_UserBlocked(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -4760,7 +4702,7 @@ func TestBookings_Create_OverlappingBlocker_UserBlocked(t *testing.T) {
 	defer fixtures.DeleteService(tx, serviceID)
 
 	// Create a time blocker for a specific time
-		blockerTime := time.Date(2099, 12, 31, 10, 0, 0, 0, time.UTC)
+	blockerTime := time.Date(2099, 12, 31, 10, 0, 0, 0, time.UTC)
 	_, err = tx.Exec(ctx, `
 		INSERT INTO time_blockers (start_time, duration_minutes, description, created_by)
 		VALUES ($1, 60, 'Staff meeting', NULL)
@@ -4808,8 +4750,6 @@ func TestBookings_Edit_OverlappingBlocker_UserBlocked(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -4836,7 +4776,7 @@ func TestBookings_Edit_OverlappingBlocker_UserBlocked(t *testing.T) {
 	defer fixtures.DeleteBooking(tx, bookingID)
 
 	// Create a time blocker for a specific time
-		blockerTime := time.Date(2099, 12, 31, 10, 0, 0, 0, time.UTC)
+	blockerTime := time.Date(2099, 12, 31, 10, 0, 0, 0, time.UTC)
 	_, err = tx.Exec(ctx, `
 		INSERT INTO time_blockers (start_time, duration_minutes, description, created_by)
 		VALUES ($1, 60, 'Staff meeting', NULL)
@@ -4985,7 +4925,6 @@ func TestGuestUser_Create_RegisteredEmailCollision(t *testing.T) {
 func TestGuestBooking_Create_Success(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	// Create guest user
 	guestReq := map[string]string{
@@ -5081,7 +5020,6 @@ func TestGuestBooking_Create_NonGuestUserID(t *testing.T) {
 func TestGuestBooking_SkipsDepositCheck(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	// Create guest user
 	guestReq := map[string]string{
@@ -5123,9 +5061,8 @@ func TestGuestBooking_SkipsDepositCheck(t *testing.T) {
 }
 
 func TestGuestBooking_BypassesAdvanceWindow(t *testing.T) {
-	
+
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	// Create guest user
 	guestReq := map[string]string{
@@ -5158,8 +5095,6 @@ func TestGuestBooking_BypassesAdvanceWindow(t *testing.T) {
 	}
 	nearTime := midday.Truncate(time.Second)
 
-	
-
 	req := CreateBookingRequest{
 		StartTime:  nearTime,
 		ServiceIDs: []string{serviceID},
@@ -5181,7 +5116,6 @@ func TestGuestBooking_BypassesAdvanceWindow(t *testing.T) {
 func TestCreateBooking_Notifications_NewBookingAlwaysCreated(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -5236,7 +5170,6 @@ func TestCreateBooking_Notifications_NewBookingAlwaysCreated(t *testing.T) {
 func TestCreateBooking_Notifications_PendingBookingWithNotes(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -5303,7 +5236,6 @@ func TestCreateBooking_Notifications_PendingBookingWithNotes(t *testing.T) {
 func TestCreateBooking_Notifications_NoPendingBookingWithoutNotes(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -6016,7 +5948,6 @@ func TestProgressBooking_DailyStampCap_SQLSubquery(t *testing.T) {
 func TestCreateBooking_OneHourAdvanceCheck(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -6071,7 +6002,6 @@ func TestCreateBooking_OneHourAdvanceCheck(t *testing.T) {
 func TestCreateBooking_ActiveBookingLimit(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -6177,7 +6107,6 @@ func TestNextWeekdayHelper(t *testing.T) {
 func TestCreateBooking_DepositSnapshot(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -6282,7 +6211,6 @@ func TestCreateBooking_DepositSnapshot(t *testing.T) {
 func TestGetBooking_WithDiscounts(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -6373,7 +6301,6 @@ func createCompletedBookingWithTime(t *testing.T, tx db.Querier, ctx context.Con
 func TestBookings_Confirm_WithCustomServiceOverrides(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -6495,7 +6422,6 @@ func TestBookings_Confirm_WithCustomServiceOverrides(t *testing.T) {
 func TestBookings_GetBooking_WithCustomServices(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -6576,7 +6502,6 @@ func TestBookings_GetBooking_WithCustomServices(t *testing.T) {
 func TestBookings_Confirm_CustomOverrideValidation(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -6665,7 +6590,6 @@ func TestBookings_Confirm_CustomOverrideValidation(t *testing.T) {
 func TestBookings_Confirm_CustomServiceNotInBooking(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -6744,7 +6668,6 @@ func TestBookings_Confirm_CustomServiceNotInBooking(t *testing.T) {
 func TestBookings_Progress_WithCustomServices(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -6919,10 +6842,8 @@ func TestDeleteBooking_WithPayments_ProcessesRefund(t *testing.T) {
 // TestDeleteBooking_NoPayments_HardDelete verifies that when a booking has no
 // payments, cancelling performs a hard delete (removes the row entirely).
 func TestDeleteBooking_NoPayments_HardDelete(t *testing.T) {
-	
-	ctx, tx := testutils.SetupTestTx(t)
 
-	
+	ctx, tx := testutils.SetupTestTx(t)
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -7066,8 +6987,6 @@ func TestRequestEditHandler_AutoApproves_NoPayments_FarFuture(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -7163,8 +7082,6 @@ func TestRequestEditHandler_AutoApproves_WithTimeChange(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -7241,8 +7158,6 @@ func TestRequestEditHandler_NoAutoApproval_WithPayments(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -7312,8 +7227,6 @@ func TestRequestEditHandler_NoAutoApproval_Within48h(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create test user: %v", err)
@@ -7372,7 +7285,6 @@ func TestRequestEditHandler_NoAutoApproval_Within48h(t *testing.T) {
 func TestCreateEditRequest_DiscountsBlockAutoApprove(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -7441,7 +7353,6 @@ func TestCreateEditRequest_DiscountsBlockAutoApprove(t *testing.T) {
 func TestCreateEditRequest_NoDiscountsStillAutoApproves(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -7506,7 +7417,6 @@ func TestCreateEditRequest_NoDiscountsStillAutoApproves(t *testing.T) {
 func TestGetAllUserBookings_CursorNotSetOnLastPage(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -7628,7 +7538,6 @@ func TestGetAllUserBookings_CursorNotSetOnLastPage(t *testing.T) {
 func TestGetAllUserBookings_TotalCountMatches(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
diff --git a/backend/handlers/bookings/cancel_reservation_test.go b/backend/handlers/bookings/cancel_reservation_test.go
index 4abeb55..02e1d51 100644
--- a/backend/handlers/bookings/cancel_reservation_test.go
+++ b/backend/handlers/bookings/cancel_reservation_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package bookings
 
diff --git a/backend/handlers/bookings/closing_time_test.go b/backend/handlers/bookings/closing_time_test.go
index 6421f5b..18cc9a2 100644
--- a/backend/handlers/bookings/closing_time_test.go
+++ b/backend/handlers/bookings/closing_time_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package bookings
 
@@ -65,8 +64,8 @@ func TestCheckClosingHours_InvalidFormat(t *testing.T) {
 	localEnd := time.Date(2026, 6, 24, 14, 0, 0, 0, london)
 
 	tests := []struct {
-		name      string
-		closeStr  string
+		name     string
+		closeStr string
 	}{
 		{"empty string", ""},
 		{"no colon", "1700"},
diff --git a/backend/handlers/bookings/dedup_test.go b/backend/handlers/bookings/dedup_test.go
index 7e9e325..977924d 100644
--- a/backend/handlers/bookings/dedup_test.go
+++ b/backend/handlers/bookings/dedup_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package bookings
 
@@ -22,7 +21,6 @@ import (
 
 func setupDedupTest(t *testing.T, tx db.Querier, ctx context.Context) (string, string, string) {
 	t.Helper()
-	
 
 	userID := createTestUser(t, 0, tx, ctx)
 	serviceID := createTestService(t, 50.00, tx, ctx)
@@ -139,7 +137,6 @@ func TestProgressBooking_UserMilestoneDedup(t *testing.T) {
 func TestNoShowApplyDepositsIfNeeded(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID := createTestUser(t, 0, tx, ctx)
 	serviceID := createTestService(t, 50.00, tx, ctx)
@@ -170,7 +167,6 @@ func TestNoShowApplyDepositsIfNeeded(t *testing.T) {
 func TestNoShowSingleNoShowDoesNotTrigger(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID := createTestUser(t, 0, tx, ctx)
 	serviceID := createTestService(t, 50.00, tx, ctx)
@@ -194,7 +190,6 @@ func TestNoShowSingleNoShowDoesNotTrigger(t *testing.T) {
 func TestNoShowOldNoShowsExcluded(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID := createTestUser(t, 0, tx, ctx)
 	serviceID := createTestService(t, 50.00, tx, ctx)
@@ -222,7 +217,6 @@ func TestNoShowOldNoShowsExcluded(t *testing.T) {
 func TestNoShowForgivenExcluded(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID := createTestUser(t, 0, tx, ctx)
 	serviceID := createTestService(t, 50.00, tx, ctx)
@@ -252,7 +246,6 @@ func TestNoShowForgivenExcluded(t *testing.T) {
 func TestThreePaidBookingsClearNoShows(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
-	
 
 	userID := createTestUser(t, 0, tx, ctx)
 	serviceID := createTestService(t, 50.00, tx, ctx)
diff --git a/backend/handlers/bookings/deposit_test.go b/backend/handlers/bookings/deposit_test.go
index 825e157..2b0da66 100644
--- a/backend/handlers/bookings/deposit_test.go
+++ b/backend/handlers/bookings/deposit_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package bookings
 
@@ -14,9 +13,9 @@ import (
 
 	"crussell/clock"
 	"crussell/db"
-	"crussell/testutils"
 	"crussell/handlers/payments"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 	"crussell/testutils/jwt"
 )
diff --git a/backend/handlers/bookings/discount_test.go b/backend/handlers/bookings/discount_test.go
index e6b2032..fa20b5c 100644
--- a/backend/handlers/bookings/discount_test.go
+++ b/backend/handlers/bookings/discount_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package bookings
 
@@ -15,9 +14,9 @@ import (
 
 	"crussell/clock"
 	"crussell/db"
-	"crussell/testutils"
 	"crussell/handlers/payments"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 
 	"github.com/go-chi/chi/v5"
diff --git a/backend/handlers/bookings/edit_requests_test.go b/backend/handlers/bookings/edit_requests_test.go
index 521a277..f50fbaf 100644
--- a/backend/handlers/bookings/edit_requests_test.go
+++ b/backend/handlers/bookings/edit_requests_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package bookings
 
@@ -34,8 +33,8 @@ import (
 
 	"crussell/clock"
 	"crussell/db"
-	"crussell/testutils"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 	"crussell/testutils/jwt"
 
@@ -1610,8 +1609,6 @@ func TestAdminApproveEditRequestHandler_WithNotesOnly(t *testing.T) {
 func TestAdminApproveEditRequestHandler_OverlapWithBooking(t *testing.T) {
 	ctx, tx := testutils.SetupTestTx(t)
 
-
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
@@ -1883,8 +1880,6 @@ func TestUserCancelBookingHandler_CleansUpEditRequest(t *testing.T) {
 func TestAdminApproveEditRequestHandler_BlockedByExceptionalClosedHours(t *testing.T) {
 	ctx, tx := testutils.SetupTestTx(t)
 
-
-
 	_, serviceID, bookingID, token := setupEditRequestTest(t, ctx, tx)
 	_ = serviceID
 
diff --git a/backend/handlers/bookings/manage.go b/backend/handlers/bookings/manage.go
index 3a33077..c8437bc 100644
--- a/backend/handlers/bookings/manage.go
+++ b/backend/handlers/bookings/manage.go
@@ -2,9 +2,8 @@ package bookings
 
 import (
 	"context"
-	"crussell/db"
 	"crussell/clock"
-	"github.com/jackc/pgx/v5"
+	"crussell/db"
 	"crussell/handlers/notifications"
 	"crussell/handlers/payments"
 	"crussell/handlers/scheduling"
@@ -14,6 +13,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"github.com/jackc/pgx/v5"
 	"log"
 	"net/http"
 	"strings"
@@ -279,7 +279,7 @@ func AdminCancelBookingHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	if refundFailed || (refundResult != nil && refundResult.RefundableAmount > 0) {
-		resp := map[string]interface{}{
+		resp := map[string]any{
 			"message": "Booking cancelled",
 		}
 		if refundResult != nil && refundResult.RefundableAmount > 0 {
@@ -932,7 +932,7 @@ func AdminCreateBookingForUserHandler(w http.ResponseWriter, r *http.Request) {
 
 	}
 
-	response := map[string]interface{}{
+	response := map[string]any{
 
 		"booking": booking,
 
@@ -988,10 +988,10 @@ type EditSnapshot struct {
 }
 
 type EditUserSummary struct {
-	ID               string  `json:"id"`
-	FullName         string  `json:"full_name"`
-	Email            *string `json:"email,omitempty"`
-	Phone            *string `json:"phone,omitempty"`
+	ID                string  `json:"id"`
+	FullName          string  `json:"full_name"`
+	Email             *string `json:"email,omitempty"`
+	Phone             *string `json:"phone,omitempty"`
 	PreviousFirstName *string `json:"previous_first_name,omitempty"`
 	PreviousLastName  *string `json:"previous_last_name,omitempty"`
 }
@@ -1462,12 +1462,12 @@ func RequestEditHandler(w http.ResponseWriter, r *http.Request) {
 					durMinutes = 60
 				}
 			} else {
-			if err := tx.QueryRow(r.Context(), `
+				if err := tx.QueryRow(r.Context(), `
 				SELECT total_duration_minutes FROM bookings WHERE id = $1
 			`, bookingID).Scan(&durMinutes); err != nil {
-				log.Printf("Failed to get duration for existing services: %v", err)
-				durMinutes = 60
-			}
+					log.Printf("Failed to get duration for existing services: %v", err)
+					durMinutes = 60
+				}
 			}
 			if durMinutes <= 0 {
 				durMinutes = 60
@@ -1504,7 +1504,7 @@ func RequestEditHandler(w http.ResponseWriter, r *http.Request) {
 		// Update booking start_time, notes, and services directly
 		if req.NewStartTime != nil || req.Notes != nil {
 			var setClauses []string
-			var args []interface{}
+			var args []any
 			argNum := 1
 			if req.NewStartTime != nil {
 				setClauses = append(setClauses, fmt.Sprintf("start_time = $%d", argNum))
@@ -1574,7 +1574,7 @@ func RequestEditHandler(w http.ResponseWriter, r *http.Request) {
 
 		w.Header().Set("Content-Type", "application/json")
 		w.WriteHeader(http.StatusOK)
-		json.NewEncoder(w).Encode(map[string]interface{}{
+		json.NewEncoder(w).Encode(map[string]any{
 			"auto_approved": true,
 			"edit_request":  editReq,
 		})
@@ -1684,7 +1684,7 @@ func AdminListEditRequestsHandler(w http.ResponseWriter, r *http.Request) {
 		JOIN users u ON ber.requested_by = u.id
 	`
 
-	var args []interface{}
+	var args []any
 
 	baseQuery += " ORDER BY ber.updated_at DESC"
 
@@ -1747,7 +1747,7 @@ func AdminListEditRequestsHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"requests": requests,
 		"total":    total,
 	})
@@ -1939,7 +1939,7 @@ func AdminApproveEditRequestHandler(w http.ResponseWriter, r *http.Request) {
 		// setClauses contains only hardcoded column name assignments ("start_time = $N", "notes = $N").
 		// Column names are never derived from user input. User values are in args and always parameterised.
 		var setClauses []string
-		var args []interface{}
+		var args []any
 		argNum := 1
 
 		if newStartTime != nil {
@@ -2153,7 +2153,7 @@ func GetMyEditRequestHandler(w http.ResponseWriter, r *http.Request) {
 		if errors.Is(err, pgx.ErrNoRows) {
 			w.Header().Set("Content-Type", "application/json")
 			w.WriteHeader(http.StatusOK)
-			json.NewEncoder(w).Encode(map[string]interface{}{
+			json.NewEncoder(w).Encode(map[string]any{
 				"edit_request": nil,
 			})
 			return
@@ -2172,7 +2172,7 @@ func GetMyEditRequestHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"edit_request": enriched,
 	})
 }
@@ -2236,7 +2236,7 @@ func GetMyEditRequestsHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"edit_requests": enrichedRequests,
 	})
 }
@@ -2293,7 +2293,7 @@ func AdminListAllEditRequestsHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"edit_requests": enrichedRequests,
 	})
 }
@@ -2342,7 +2342,7 @@ func AdminGetBookingEditRequestHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"edit_request": enriched,
 	})
 }
diff --git a/backend/handlers/bookings/overlap_test.go b/backend/handlers/bookings/overlap_test.go
index abfb521..fd8bdd2 100644
--- a/backend/handlers/bookings/overlap_test.go
+++ b/backend/handlers/bookings/overlap_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package bookings
 
@@ -1301,7 +1300,7 @@ func TestAdminCreateBooking_Weekday_BST_Boundary(t *testing.T) {
 	// Compute weekStart the same way the handler does: from the booking time's
 	// London weekday, find Monday's date, store as UTC midnight.
 	bkLondon := sunday2330UTC.In(londonLocation) // 00:30 BST Monday
-	daysToMonday := int(bkLondon.Weekday())       // Monday in Go = 1
+	daysToMonday := int(bkLondon.Weekday())      // Monday in Go = 1
 	if daysToMonday == 0 {
 		daysToMonday = 7
 	}
@@ -2182,10 +2181,10 @@ func TestAdminReserveSlot_CleansUpAnonReservation(t *testing.T) {
 
 	w := makeIPRequest(http.HandlerFunc(AdminReserveSlotHandler), "POST", "/api/admin/bookings/reserve",
 		&AdminReserveSlotRequest{
-			StartTime:        future,
-			ServiceIDs:       []string{serviceID},
-			DurationMinutes:  60,
-			ReservationType:  "walkin",
+			StartTime:       future,
+			ServiceIDs:      []string{serviceID},
+			DurationMinutes: 60,
+			ReservationType: "walkin",
 		}, token, testIP, adminID, ctx)
 
 	if w.Code != http.StatusCreated {
diff --git a/backend/handlers/bookings/reserve.go b/backend/handlers/bookings/reserve.go
index 1e2264c..0108be8 100644
--- a/backend/handlers/bookings/reserve.go
+++ b/backend/handlers/bookings/reserve.go
@@ -80,8 +80,8 @@ func ReserveSlotHandler(w http.ResponseWriter, r *http.Request) {
 	hasAuth := hasUser && userID != ""
 	if !hasAuth {
 		authHeader := r.Header.Get("Authorization")
-		if strings.HasPrefix(authHeader, "Bearer ") {
-			tokenString := strings.TrimPrefix(authHeader, "Bearer ")
+		if after, ok := strings.CutPrefix(authHeader, "Bearer "); ok {
+			tokenString := after
 			var err error
 			userID, _, _, err = auth.VerifyToken(tokenString, r.Context())
 			if err != nil {
diff --git a/backend/handlers/bookings/reserve_test.go b/backend/handlers/bookings/reserve_test.go
index f5ca538..1c5dd28 100644
--- a/backend/handlers/bookings/reserve_test.go
+++ b/backend/handlers/bookings/reserve_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package bookings
 
diff --git a/backend/handlers/bookings/testmain_test.go b/backend/handlers/bookings/testmain_test.go
index ed84da8..6aad8d1 100644
--- a/backend/handlers/bookings/testmain_test.go
+++ b/backend/handlers/bookings/testmain_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package bookings
 
diff --git a/backend/handlers/bookings/trigger_test.go b/backend/handlers/bookings/trigger_test.go
index 1fbeeb7..a8fd41b 100644
--- a/backend/handlers/bookings/trigger_test.go
+++ b/backend/handlers/bookings/trigger_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package bookings
 
diff --git a/backend/handlers/notifications/notifications.go b/backend/handlers/notifications/notifications.go
index 8f33e91..859068e 100644
--- a/backend/handlers/notifications/notifications.go
+++ b/backend/handlers/notifications/notifications.go
@@ -201,7 +201,6 @@ func GetNotifications(w http.ResponseWriter, r *http.Request) {
 		NextCursor:    nextCursor,
 	}
 
-
 	if err := json.NewEncoder(w).Encode(resp); err != nil {
 		log.Printf("Failed to encode response: %v", err)
 		http.Error(w, "Internal server error", http.StatusInternalServerError)
@@ -222,7 +221,6 @@ func GetUnreadCount(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-
 	if err := json.NewEncoder(w).Encode(map[string]int{"count": count}); err != nil {
 		log.Printf("Failed to encode response: %v", err)
 		http.Error(w, "Internal server error", http.StatusInternalServerError)
@@ -269,13 +267,12 @@ func AcknowledgeNotification(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-
 	json.NewEncoder(w).Encode(map[string]string{
 		"status": "ok",
 	})
 }
 
-func AcknowledgePendingBookingNotification(tx interface{}, ctx context.Context, bookingID string) error {
+func AcknowledgePendingBookingNotification(tx any, ctx context.Context, bookingID string) error {
 	query := `
 		UPDATE admin_notifications 
 		SET acknowledged_at = NOW() 
@@ -284,7 +281,7 @@ func AcknowledgePendingBookingNotification(tx interface{}, ctx context.Context,
 
 	// Use type assertion to get the Exec method - pgx.Tx satisfies this interface
 	execer, ok := tx.(interface {
-		Exec(ctx context.Context, sql string, arguments ...interface{}) (pgconn.CommandTag, error)
+		Exec(ctx context.Context, sql string, arguments ...any) (pgconn.CommandTag, error)
 	})
 	if !ok {
 		log.Printf("Warning: cannot acknowledge notification - tx does not satisfy Execer interface for booking %s", bookingID)
diff --git a/backend/handlers/notifications/notifications_extended_test.go b/backend/handlers/notifications/notifications_extended_test.go
index d0141c9..d89b362 100644
--- a/backend/handlers/notifications/notifications_extended_test.go
+++ b/backend/handlers/notifications/notifications_extended_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package notifications
 
@@ -14,8 +13,8 @@ import (
 	"time"
 
 	"crussell/db"
-	"crussell/testutils"
 	"crussell/mw"
+	"crussell/testutils"
 
 	"github.com/go-chi/chi/v5"
 )
@@ -571,5 +570,3 @@ func createNotificationWithBooking(t *testing.T, ctx context.Context, q db.Queri
 	}
 	return notificationID
 }
-
-
diff --git a/backend/handlers/notifications/notifications_test.go b/backend/handlers/notifications/notifications_test.go
index b8037e7..c4b15b3 100644
--- a/backend/handlers/notifications/notifications_test.go
+++ b/backend/handlers/notifications/notifications_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package notifications
 
@@ -25,8 +24,8 @@ import (
 	"time"
 
 	"crussell/clock"
-	"crussell/testutils"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 
 	"github.com/go-chi/chi/v5"
diff --git a/backend/handlers/notifications/testmain_test.go b/backend/handlers/notifications/testmain_test.go
index 1d05e7b..2562600 100644
--- a/backend/handlers/notifications/testmain_test.go
+++ b/backend/handlers/notifications/testmain_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package notifications
 
diff --git a/backend/handlers/payments/discount_preview_test.go b/backend/handlers/payments/discount_preview_test.go
index 18e7270..c6e1e34 100644
--- a/backend/handlers/payments/discount_preview_test.go
+++ b/backend/handlers/payments/discount_preview_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package payments
 
@@ -13,8 +12,8 @@ import (
 
 	"crussell/clock"
 	"crussell/db"
-	"crussell/testutils"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 	"crussell/testutils/jwt"
 
diff --git a/backend/handlers/payments/giftcards.go b/backend/handlers/payments/giftcards.go
index 41dec6a..6637ce4 100644
--- a/backend/handlers/payments/giftcards.go
+++ b/backend/handlers/payments/giftcards.go
@@ -11,8 +11,8 @@ import (
 	"strings"
 	"time"
 
-	"crussell/db"
 	"crussell/clock"
+	"crussell/db"
 	"crussell/internal/square"
 	"crussell/internal/validators"
 	"crussell/mw"
@@ -160,7 +160,7 @@ func GetGiftCards(w http.ResponseWriter, r *http.Request) {
 	}
 
 	var gcTotal int
-	var gcListArgs []interface{}
+	var gcListArgs []any
 
 	gcListQuery := fmt.Sprintf(`
 		SELECT id, total_funds_added, amount_remaining, created_at, is_inventory
@@ -170,7 +170,7 @@ func GetGiftCards(w http.ResponseWriter, r *http.Request) {
 
 	if searchTerm != "" {
 		searchPattern := "%" + searchTerm + "%"
-		gcListArgs = []interface{}{searchPattern}
+		gcListArgs = []any{searchPattern}
 
 		if cursorStr != "" {
 			cursorCreatedAt, cursorID, err := validators.ParseCursor(cursorStr)
@@ -202,7 +202,7 @@ func GetGiftCards(w http.ResponseWriter, r *http.Request) {
 	// transaction (single connection).
 	gcTotal = 0
 	if whereSQL != "" {
-		countArgs := []interface{}{}
+		countArgs := []any{}
 		if searchTerm != "" {
 			countArgs = append(countArgs, "%"+searchTerm+"%")
 		}
@@ -243,7 +243,7 @@ func GetGiftCards(w http.ResponseWriter, r *http.Request) {
 
 	var ubTotal int
 	var ubListQuery string
-	var ubListArgs []interface{}
+	var ubListArgs []any
 
 	if searchTerm != "" {
 		searchPattern := "%" + searchTerm + "%"
@@ -258,7 +258,7 @@ func GetGiftCards(w http.ResponseWriter, r *http.Request) {
 			   OR u.email ILIKE $1
 			ORDER BY b.updated_at DESC
 		`
-		ubListArgs = []interface{}{searchPattern}
+		ubListArgs = []any{searchPattern}
 	} else {
 		ubListQuery = `
 			SELECT
@@ -267,7 +267,7 @@ func GetGiftCards(w http.ResponseWriter, r *http.Request) {
 			JOIN users u ON b.user_id = u.id
 			ORDER BY b.updated_at DESC
 		`
-		ubListArgs = []interface{}{}
+		ubListArgs = []any{}
 	}
 
 	ubRows, err := db.Conn.Query(ctx, ubListQuery, ubListArgs...)
@@ -736,7 +736,7 @@ func RedeemGiftCard(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.WriteHeader(http.StatusOK)
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"status":          "success",
 		"amount_redeemed": amountRemaining,
 	})
@@ -1065,7 +1065,7 @@ func BuyGiftCard(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.WriteHeader(http.StatusCreated)
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"status": "success",
 		"code":   cardID,
 		"amount": amountPounds,
@@ -1137,7 +1137,7 @@ func GetExpiredBalances(w http.ResponseWriter, r *http.Request) {
 		balances = []ExpiredBalance{}
 	}
 
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"expired_balances": balances,
 		"total":            len(balances),
 	})
diff --git a/backend/handlers/payments/giftcards_test.go b/backend/handlers/payments/giftcards_test.go
index f1bc837..3e710c5 100644
--- a/backend/handlers/payments/giftcards_test.go
+++ b/backend/handlers/payments/giftcards_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package payments
 
@@ -23,7 +22,6 @@ import (
 	"github.com/jackc/pgx/v5"
 )
 
-
 func TestAdminCreateGiftCard(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
diff --git a/backend/handlers/payments/handlers.go b/backend/handlers/payments/handlers.go
index 71cd23f..0d95fc0 100644
--- a/backend/handlers/payments/handlers.go
+++ b/backend/handlers/payments/handlers.go
@@ -2,8 +2,8 @@ package payments
 
 import (
 	"context"
-	"crussell/db"
 	"crussell/clock"
+	"crussell/db"
 	"crussell/internal/square"
 	"crussell/internal/validators"
 	"crussell/mw"
@@ -1943,7 +1943,7 @@ func AcquirePaymentLock(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"status":    "locked",
 		"ttl_min":   PaymentLockDuration,
 		"bookingID": bookingID,
diff --git a/backend/handlers/payments/loyalty.go b/backend/handlers/payments/loyalty.go
index 7346922..3893106 100644
--- a/backend/handlers/payments/loyalty.go
+++ b/backend/handlers/payments/loyalty.go
@@ -150,8 +150,7 @@ func ApplyLoyaltyRedemption(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"success":         true,
 		"discount_amount": discountAmount,
 	})
diff --git a/backend/handlers/payments/loyalty_test.go b/backend/handlers/payments/loyalty_test.go
index e5334b6..8ced6f1 100644
--- a/backend/handlers/payments/loyalty_test.go
+++ b/backend/handlers/payments/loyalty_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package payments
 
@@ -13,8 +12,8 @@ import (
 
 	"crussell/clock"
 	"crussell/db"
-	"crussell/testutils"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 	"crussell/testutils/jwt"
 
diff --git a/backend/handlers/payments/payment_status_test.go b/backend/handlers/payments/payment_status_test.go
index 5d87755..6ee91b3 100644
--- a/backend/handlers/payments/payment_status_test.go
+++ b/backend/handlers/payments/payment_status_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package payments
 
@@ -11,8 +10,8 @@ import (
 	"time"
 
 	"crussell/db"
-	"crussell/testutils"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 	"crussell/testutils/jwt"
 
diff --git a/backend/handlers/payments/payments_test.go b/backend/handlers/payments/payments_test.go
index 21bb20f..5aa02b4 100644
--- a/backend/handlers/payments/payments_test.go
+++ b/backend/handlers/payments/payments_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package payments
 
@@ -16,8 +15,8 @@ import (
 
 	"crussell/clock"
 	"crussell/db"
-	"crussell/testutils"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 	"crussell/testutils/jwt"
 
diff --git a/backend/handlers/payments/refund_exclude_test.go b/backend/handlers/payments/refund_exclude_test.go
index 3f34c77..cb813ee 100644
--- a/backend/handlers/payments/refund_exclude_test.go
+++ b/backend/handlers/payments/refund_exclude_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package payments
 
diff --git a/backend/handlers/payments/refunds_test.go b/backend/handlers/payments/refunds_test.go
index 6721b3e..294b3f2 100644
--- a/backend/handlers/payments/refunds_test.go
+++ b/backend/handlers/payments/refunds_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package payments
 
@@ -154,7 +153,7 @@ func TestProcessCancellationRefund_CreatesRefundRecords(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	userID, err := 	fixtures.CreateTestUser(tx)
+	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
 	}
@@ -210,7 +209,7 @@ func TestProcessCancellationRefund_NoRefundWhenNotNeeded(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	userID, err := 	fixtures.CreateTestUser(tx)
+	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
 	}
@@ -246,7 +245,7 @@ func TestProcessCancellationRefund_NoPaymentsNoop(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	userID, err := 	fixtures.CreateTestUser(tx)
+	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
 	}
@@ -289,7 +288,7 @@ func TestProcessCancellationRefund_GiftCardCreditsUserBalance(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	userID, err := 	fixtures.CreateTestUser(tx)
+	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
 	}
@@ -377,7 +376,7 @@ func TestProcessCancellationRefund_CashCreditsUserBalance(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	userID, err := 	fixtures.CreateTestUser(tx)
+	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
 	}
@@ -432,7 +431,7 @@ func TestProcessCancellationRefund_CardSquareRefundWithoutBalanceCredit(t *testi
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	userID, err := 	fixtures.CreateTestUser(tx)
+	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
 	}
@@ -507,7 +506,7 @@ func TestProcessCancellationRefund_DiscountPaymentSkipped(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	userID, err := 	fixtures.CreateTestUser(tx)
+	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
 	}
@@ -562,7 +561,7 @@ func TestProcessCancellationRefund_OnTheHousePaymentSkipped(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	userID, err := 	fixtures.CreateTestUser(tx)
+	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
 	}
@@ -621,7 +620,7 @@ func TestProcessCancellationRefund_MissingUserID_LogsWarning(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	userID, err := 	fixtures.CreateTestUser(tx)
+	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
 	}
@@ -687,7 +686,7 @@ func TestProcessCancellationRefund_GuestGiftcardDoesNotCreditBalance(t *testing.
 	ctx, tx := testutils.SetupTestTx(t)
 
 	// Create a user and promote them to guest role.
-	userID, err := 	fixtures.CreateTestUser(tx)
+	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
 	}
@@ -758,7 +757,7 @@ func TestProcessCancellationRefund_GuestCashDoesNotCreditBalance(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	userID, err := 	fixtures.CreateTestUser(tx)
+	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
 	}
@@ -824,7 +823,7 @@ func TestProcessCancellationRefund_SplitPayment_DeduplicatesSquareRefund(t *test
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-	userID, err := 	fixtures.CreateTestUser(tx)
+	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
 	}
diff --git a/backend/handlers/payments/testmain_test.go b/backend/handlers/payments/testmain_test.go
index ce50f0c..4f23455 100644
--- a/backend/handlers/payments/testmain_test.go
+++ b/backend/handlers/payments/testmain_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package payments
 
diff --git a/backend/handlers/payments/till_test.go b/backend/handlers/payments/till_test.go
index be20d05..4baf09b 100644
--- a/backend/handlers/payments/till_test.go
+++ b/backend/handlers/payments/till_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package payments
 
@@ -25,7 +24,6 @@ func TestCreateTillSale_OnTheHouse(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-
 	adminID, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create admin user: %v", err)
@@ -104,7 +102,6 @@ func TestCreateTillSale_Idempotency(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-
 	adminID, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create admin user: %v", err)
@@ -192,7 +189,6 @@ func TestCreateTillSale_CreatesGiftCardTransaction(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-
 	adminID, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create admin user: %v", err)
@@ -294,7 +290,6 @@ func TestCreateTillSale_TopupOnRedeemedCard(t *testing.T) {
 	t.Parallel()
 	ctx, tx := testutils.SetupTestTx(t)
 
-
 	adminID, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create admin user: %v", err)
diff --git a/backend/handlers/payments/vat_test.go b/backend/handlers/payments/vat_test.go
index ad791fa..3e17abb 100644
--- a/backend/handlers/payments/vat_test.go
+++ b/backend/handlers/payments/vat_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package payments
 
diff --git a/backend/handlers/portfolio/images.go b/backend/handlers/portfolio/images.go
index aa8af32..011833c 100644
--- a/backend/handlers/portfolio/images.go
+++ b/backend/handlers/portfolio/images.go
@@ -3,8 +3,8 @@ package portfolio
 import (
 	"bytes"
 	"context"
-	"crussell/db"
 	"crussell/clock"
+	"crussell/db"
 	"crussell/internal/images"
 	"crussell/internal/s3"
 	"crussell/internal/validators"
@@ -165,8 +165,8 @@ func ListImages(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	filterClauses := ""
-	filterArgs := []interface{}{}
+	var filterClauses strings.Builder
+	filterArgs := []any{}
 
 	for key, values := range r.URL.Query() {
 		if len(values) == 0 || values[0] == "" {
@@ -190,14 +190,14 @@ func ListImages(w http.ResponseWriter, r *http.Request) {
 					return
 				}
 
-				filterClauses += fmt.Sprintf(" AND $%d::text = ANY(tag_names)", len(filterArgs)+1)
+				filterClauses.WriteString(fmt.Sprintf(" AND $%d::text = ANY(tag_names)", len(filterArgs)+1))
 				filterArgs = append(filterArgs, category+":"+value)
 			}
 		}
 	}
 
 	var query string
-	var args []interface{}
+	var args []any
 
 	const formatCols = `, full_avif_url, full_webp_url, full_jpg_url, full_jxl_url, thumb_avif_url, thumb_webp_url, thumb_jpg_url`
 
@@ -226,16 +226,16 @@ func ListImages(w http.ResponseWriter, r *http.Request) {
 			FROM images, unnest(tag_names) as t
 			WHERE %s%s
 			GROUP BY id
-		`, formatCols, similaritySum, whereClause, filterClauses)
+		`, formatCols, similaritySum, whereClause, filterClauses.String())
 
-		var cursorArgs []interface{}
+		var cursorArgs []any
 		if cursorStr != "" {
 			cursorCreatedAt, cursorID, err := validators.ParseCursor(cursorStr)
 			if err != nil {
 				http.Error(w, "Invalid cursor: "+err.Error(), http.StatusBadRequest)
 				return
 			}
-			cursorArgs = []interface{}{cursorCreatedAt, cursorID}
+			cursorArgs = []any{cursorCreatedAt, cursorID}
 			havingIdx := len(cleanTags) + len(filterArgs) + 1
 			query += fmt.Sprintf(" HAVING (created_at, id) < ($%d, $%d)", havingIdx, havingIdx+1)
 		}
@@ -244,7 +244,7 @@ func ListImages(w http.ResponseWriter, r *http.Request) {
 		argOffset = len(filterArgs) + len(cleanTags) + len(cursorArgs)
 		query += fmt.Sprintf(" LIMIT $%d", argOffset+1)
 
-		queryArgs := make([]interface{}, len(filterArgs)+len(cleanTags)+len(cursorArgs)+1)
+		queryArgs := make([]any, len(filterArgs)+len(cleanTags)+len(cursorArgs)+1)
 		copy(queryArgs, filterArgs)
 		for i, t := range cleanTags {
 			queryArgs[len(filterArgs)+i] = t
@@ -264,9 +264,9 @@ func ListImages(w http.ResponseWriter, r *http.Request) {
 			       similarity(t, $%d) as relevance
 			FROM images, unnest(tag_names) as t
 			WHERE 1=1%s AND t ILIKE '%%' || $%d || '%%'
-		`, formatCols, searchIdx, searchIdx, filterClauses, searchIdx)
+		`, formatCols, searchIdx, searchIdx, filterClauses.String(), searchIdx)
 
-		cursorArgs := []interface{}{}
+		cursorArgs := []any{}
 		if cursorStr != "" {
 			cursorCreatedAt, cursorID, err := validators.ParseCursor(cursorStr)
 			if err != nil {
@@ -280,7 +280,7 @@ func ListImages(w http.ResponseWriter, r *http.Request) {
 		query += " ORDER BY match_priority DESC, relevance DESC, created_at DESC, id DESC"
 		query += fmt.Sprintf(" LIMIT $%d", searchIdx+1+len(cursorArgs))
 
-		queryArgs := make([]interface{}, searchIdx+1+len(cursorArgs))
+		queryArgs := make([]any, searchIdx+1+len(cursorArgs))
 		copy(queryArgs[:argOffset], filterArgs)
 		queryArgs[argOffset] = searchPattern
 		for i, ca := range cursorArgs {
@@ -294,7 +294,7 @@ func ListImages(w http.ResponseWriter, r *http.Request) {
 			SELECT id, url, thumbnail_url, tag_names, created_at%s, 0 as match_count, 0.0 as relevance
 			FROM images
 			WHERE 1=1%s
-		`, formatCols, filterClauses)
+		`, formatCols, filterClauses.String())
 
 		if cursorStr != "" {
 			cursorCreatedAt, cursorID, err := validators.ParseCursor(cursorStr)
@@ -310,7 +310,7 @@ func ListImages(w http.ResponseWriter, r *http.Request) {
 		query += " ORDER BY created_at DESC, id DESC"
 		query += fmt.Sprintf(" LIMIT $%d", argOffset+1)
 
-		queryArgs := make([]interface{}, len(filterArgs)+1)
+		queryArgs := make([]any, len(filterArgs)+1)
 		copy(queryArgs, filterArgs)
 		queryArgs[len(filterArgs)] = limit
 		args = queryArgs
@@ -394,7 +394,7 @@ func ListTags(w http.ResponseWriter, r *http.Request) {
 	}
 
 	var query string
-	var args []interface{}
+	var args []any
 
 	// Query tags from images.tag_names column (stored as array)
 	if q != "" {
@@ -409,7 +409,7 @@ func ListTags(w http.ResponseWriter, r *http.Request) {
 			ORDER BY tag
 			LIMIT 20
 		`
-		args = []interface{}{q}
+		args = []any{q}
 	} else {
 		query = `
 			SELECT DISTINCT tag
@@ -484,7 +484,7 @@ func ListFilters(w http.ResponseWriter, r *http.Request) {
 
 	// Build base query
 	baseQuery := "SELECT DISTINCT id FROM images WHERE 1=1"
-	args := []interface{}{}
+	args := []any{}
 	argNum := 1
 
 	if tagFilter != "" {
@@ -507,7 +507,7 @@ func ListFilters(w http.ResponseWriter, r *http.Request) {
 
 	// Build category filters for OTHER categories
 	otherFilters := make([]string, 0)
-	otherArgs := make([]interface{}, len(args))
+	otherArgs := make([]any, len(args))
 	copy(otherArgs, args)
 	otherArgNum := argNum
 	for cat, val := range selectedCategories {
@@ -709,7 +709,7 @@ func UploadImage(w http.ResponseWriter, r *http.Request) {
 	tagsStr := r.FormValue("tags")
 	tags := []string{}
 	if tagsStr != "" {
-		for _, t := range strings.Split(tagsStr, ",") {
+		for t := range strings.SplitSeq(tagsStr, ",") {
 			if trimmed := strings.TrimSpace(t); trimmed != "" {
 				tags = append(tags, trimmed)
 			}
@@ -1034,11 +1034,11 @@ func extractKey(url string) string {
 	// URL format: https://endpoint/bucket/portfolio/1234567890.jpg
 	// Need to return: portfolio/1234567890.jpg
 	// Find the bucket segment: skip past scheme://endpoint/
-	idx := strings.Index(url, "://")
-	if idx == -1 {
+	_, after, ok := strings.Cut(url, "://")
+	if !ok {
 		return url
 	}
-	rest := url[idx+3:] // skip "://"
+	rest := after // skip "://"
 	// Now rest = "endpoint/bucket/portfolio/1234567890.jpg"
 	// Skip first path segment (endpoint)
 	slashIdx := strings.Index(rest, "/")
diff --git a/backend/handlers/portfolio/images_test.go b/backend/handlers/portfolio/images_test.go
index fb1f2be..dcec670 100644
--- a/backend/handlers/portfolio/images_test.go
+++ b/backend/handlers/portfolio/images_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 // Package portfolio contains tests for portfolio image management endpoints.
 //
@@ -27,8 +26,8 @@ import (
 	"strings"
 	"testing"
 
-	"crussell/testutils"
 	"crussell/mw"
+	"crussell/testutils"
 
 	"github.com/go-chi/chi/v5"
 	"github.com/kovidgoyal/imaging"
diff --git a/backend/handlers/portfolio/testmain_test.go b/backend/handlers/portfolio/testmain_test.go
index 71a7551..1b3166a 100644
--- a/backend/handlers/portfolio/testmain_test.go
+++ b/backend/handlers/portfolio/testmain_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package portfolio
 
diff --git a/backend/handlers/scheduling/default-hours.go b/backend/handlers/scheduling/default-hours.go
index 9052055..5cda33c 100644
--- a/backend/handlers/scheduling/default-hours.go
+++ b/backend/handlers/scheduling/default-hours.go
@@ -8,8 +8,8 @@ import (
 	"strings"
 	"time"
 
-	"crussell/db"
 	"crussell/clock"
+	"crussell/db"
 	"crussell/internal/validators"
 	"crussell/mw"
 	"log"
@@ -308,17 +308,17 @@ func isValidTime15Min(t string) bool {
 }
 
 // --- helper: sqlIn generates IN queries dynamically for Postgres ---
-func sqlIn(query string, args []int) (string, []interface{}, error) {
-	inArgs := []interface{}{}
-	placeholders := ""
+func sqlIn(query string, args []int) (string, []any, error) {
+	inArgs := []any{}
+	var placeholders strings.Builder
 	for i, arg := range args {
 		if i > 0 {
-			placeholders += ","
+			placeholders.WriteString(",")
 		}
-		placeholders += fmt.Sprintf("$%d", i+1)
+		placeholders.WriteString(fmt.Sprintf("$%d", i+1))
 		inArgs = append(inArgs, arg)
 	}
-	query = fmt.Sprintf(query, placeholders)
+	query = fmt.Sprintf(query, placeholders.String())
 	return query, inArgs, nil
 }
 
diff --git a/backend/handlers/scheduling/scheduled_cleanup_test.go b/backend/handlers/scheduling/scheduled_cleanup_test.go
index dd3724a..4921149 100644
--- a/backend/handlers/scheduling/scheduled_cleanup_test.go
+++ b/backend/handlers/scheduling/scheduled_cleanup_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package scheduling
 
diff --git a/backend/handlers/scheduling/scheduling_test.go b/backend/handlers/scheduling/scheduling_test.go
index 3c8ffbe..9fd1a3f 100644
--- a/backend/handlers/scheduling/scheduling_test.go
+++ b/backend/handlers/scheduling/scheduling_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package scheduling
 
@@ -1023,7 +1022,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_NonAdmin(t *testing.T) {
 	ctx, tx := resetTestData(t)
 
 	// Create a time blocker for 2026-03-16 10:00-11:00 (Monday - an open day)
-		blockerTime := time.Date(2026, 3, 16, 10, 0, 0, 0, time.UTC)
+	blockerTime := time.Date(2026, 3, 16, 10, 0, 0, 0, time.UTC)
 	_, err := tx.Exec(ctx, `
 		INSERT INTO time_blockers (start_time, duration_minutes, description, created_by)
 		VALUES ($1, 60, 'Staff Meeting', NULL)
@@ -1091,7 +1090,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin(t *testing.T) {
 	ctx, tx := resetTestData(t)
 
 	// Create a time blocker for 2026-03-16 10:00-11:00 (Monday - open day)
-		blockerTime := time.Date(2026, 3, 16, 10, 0, 0, 0, time.UTC)
+	blockerTime := time.Date(2026, 3, 16, 10, 0, 0, 0, time.UTC)
 	_, err := tx.Exec(ctx, `
 		INSERT INTO time_blockers (start_time, duration_minutes, description, created_by)
 		VALUES ($1, 60, 'Staff Meeting', NULL)
@@ -1309,7 +1308,7 @@ func getWorkingHoursForDate(t *testing.T, ctx context.Context, date string) (sta
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_MultipleBlockers(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
-	
+
 	// Create two blockers on Tuesday 2026-03-17 (open 09:00-17:00):
 	// 10:00-11:00 (Staff Meeting) and 14:00-15:00 (Training)
 	b1 := time.Date(2026, 3, 17, 10, 0, 0, 0, time.UTC)
@@ -1353,7 +1352,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_MultipleBlockers(t *test
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_BlockerAndBooking(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
-	
+
 	// Tuesday 2026-03-17 (open 09:00-17:00)
 	// Create a booking at 11:00-12:00 and a blocker at 14:00-15:00
 	bookingStart := time.Date(2026, 3, 17, 11, 0, 0, 0, time.UTC)
@@ -1413,7 +1412,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_BlockerAndBooking(t *tes
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_AllDayBlocker(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
-	
+
 	// Tuesday 2026-03-17 (open 09:00-17:00) — block entire open period
 	blockerTime := time.Date(2026, 3, 17, 9, 0, 0, 0, time.UTC)
 	tx.Exec(ctx, `INSERT INTO time_blockers (start_time, duration_minutes, description, created_by) VALUES ($1, 480, 'All day closure', NULL)`, blockerTime)
@@ -1440,7 +1439,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_AllDayBlocker(t *testing
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_NonOverlappingBlocker(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
-	
+
 	// Tuesday 2026-03-17 (open 09:00-17:00) — blocker at 17:00-18:00 (after close)
 	blockerTime := time.Date(2026, 3, 17, 17, 0, 0, 0, time.UTC)
 	tx.Exec(ctx, `INSERT INTO time_blockers (start_time, duration_minutes, description, created_by) VALUES ($1, 60, 'After hours cleaning', NULL)`, blockerTime)
@@ -1476,7 +1475,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_NonOverlappingBlocker(t
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_MultiDay(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
-	
+
 	// Blockers on Tue 2026-03-17 10:00-11:00 and Wed 2026-03-18 14:00-15:00
 	b1 := time.Date(2026, 3, 17, 10, 0, 0, 0, time.UTC)
 	b2 := time.Date(2026, 3, 18, 14, 0, 0, 0, time.UTC)
@@ -1525,7 +1524,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_MultiDay(t *testing.T) {
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_BoundaryStart(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
-	
+
 	// Tuesday 2026-03-17 (open 09:00-17:00) — blocker at 09:00-10:00 (start of day)
 	blockerTime := time.Date(2026, 3, 17, 9, 0, 0, 0, time.UTC)
 	tx.Exec(ctx, `INSERT INTO time_blockers (start_time, duration_minutes, description, created_by) VALUES ($1, 60, 'Morning setup', NULL)`, blockerTime)
@@ -1561,7 +1560,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_BoundaryStart(t *testing
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_BoundaryEnd(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
-	
+
 	// Tuesday 2026-03-17 (open 09:00-17:00) — blocker at 16:00-17:00 (end of day)
 	blockerTime := time.Date(2026, 3, 17, 16, 0, 0, 0, time.UTC)
 	tx.Exec(ctx, `INSERT INTO time_blockers (start_time, duration_minutes, description, created_by) VALUES ($1, 60, 'End of day cleanup', NULL)`, blockerTime)
@@ -1597,7 +1596,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_BoundaryEnd(t *testing.T
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_OutOfHours(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
-	
+
 	// Tuesday 2026-03-17 — blocker at 10:00-11:00
 	blockerTime := time.Date(2026, 3, 17, 10, 0, 0, 0, time.UTC)
 	tx.Exec(ctx, `INSERT INTO time_blockers (start_time, duration_minutes, description, created_by) VALUES ($1, 60, 'Morning Meeting', NULL)`, blockerTime)
@@ -1639,7 +1638,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_OutOfHours(t *testing.T)
 func TestScheduling_GetAvailableHours_WithBlocker_NonAdmin_Regression(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
-	
+
 	// Tuesday 2026-03-17 — blocker at 10:00-11:00
 	blockerTime := time.Date(2026, 3, 17, 10, 0, 0, 0, time.UTC)
 	tx.Exec(ctx, `INSERT INTO time_blockers (start_time, duration_minutes, description, created_by) VALUES ($1, 60, 'Staff Meeting', NULL)`, blockerTime)
@@ -1686,7 +1685,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_Recurring(t *testing.T)
 	// No t.Parallel() — GetAvailableHours cleanup operations can deadlock with
 	// concurrent test transactions on the shared test database.
 	ctx, tx := resetTestData(t)
-	
+
 	// Daily recurring blocker 12:00-13:00 starting Mon 2026-03-16
 	startTime := time.Date(2026, 3, 16, 12, 0, 0, 0, time.UTC)
 	cronExpr := "0 12 * * *" // Every day at 12:00
@@ -1730,7 +1729,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_Recurring(t *testing.T)
 // RESERVATION:admin time_blocker entries are also subtracted from admin slots.
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_Reservation(t *testing.T) {
 	ctx, tx := resetTestData(t)
-	
+
 	// Create a real admin user to satisfy FK constraint, then simulate a reservation
 	adminID, err := fixtures.CreateTestAdminUser(tx)
 	if err != nil {
@@ -1774,7 +1773,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_Reservation(t *testing.T
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_Reservation_NonAdmin(t *testing.T) {
 	// Not parallel (see above)
 	ctx, tx := resetTestData(t)
-	
+
 	reservationTime := time.Date(2026, 3, 17, 10, 0, 0, 0, time.UTC)
 	tx.Exec(ctx, `
 		INSERT INTO time_blockers (start_time, duration_minutes, description, created_by)
@@ -1812,7 +1811,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_Reservation_NonAdmin(t *
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_OverlappingBlockers(t *testing.T) {
 
 	ctx, tx := resetTestData(t)
-	
+
 	// Two overlapping blockers on Tue 2026-03-17: 10:00-12:00 and 11:00-13:00
 	b1 := time.Date(2026, 3, 17, 10, 0, 0, 0, time.UTC)
 	b2 := time.Date(2026, 3, 17, 11, 0, 0, 0, time.UTC)
@@ -1854,7 +1853,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_OverlappingBlockers(t *t
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_AdjacentBoundaries(t *testing.T) {
 
 	ctx, tx := resetTestData(t)
-	
+
 	// Tue 2026-03-17: booking 10:00-11:00, blocker 11:00-12:00 (adjacent)
 	bookingStart := time.Date(2026, 3, 17, 10, 0, 0, 0, time.UTC)
 	bookingEnd := bookingStart.Add(60 * time.Minute)
@@ -1899,7 +1898,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_AdjacentBoundaries(t *te
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_MidnightBlocker(t *testing.T) {
 
 	ctx, tx := resetTestData(t)
-	
+
 	// Use the first open day found and the following day
 	tueStart, tueEnd, tueOpen := getWorkingHoursForDate(t, ctx, "2026-03-17")
 	wedStart, _, wedOpen := getWorkingHoursForDate(t, ctx, "2026-03-18")
@@ -1987,7 +1986,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_NoBlockers(t *testing.T)
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_ClosedDayBlocker(t *testing.T) {
 
 	ctx, tx := resetTestData(t)
-	
+
 	// Sunday 2026-03-22 is closed. Blocker at 10:00-11:00.
 	blockerTime := time.Date(2026, 3, 22, 10, 0, 0, 0, time.UTC)
 	tx.Exec(ctx, `INSERT INTO time_blockers (start_time, duration_minutes, description, created_by) VALUES ($1, 60, 'Sunday Maintenance', NULL)`, blockerTime)
@@ -2017,7 +2016,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_ClosedDayBlocker(t *test
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_MultiDayRangePartial(t *testing.T) {
 
 	ctx, tx := resetTestData(t)
-	
+
 	// Blocker only on Tuesday (2026-03-17) at 10:00-11:00
 	blockerTime := time.Date(2026, 3, 17, 10, 0, 0, 0, time.UTC)
 	tx.Exec(ctx, `INSERT INTO time_blockers (start_time, duration_minutes, description, created_by) VALUES ($1, 60, 'Tue Only Blocker', NULL)`, blockerTime)
@@ -2065,7 +2064,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_MultiDayRangePartial(t *
 func TestScheduling_GetAvailableHours_WithBlocker_Admin_ExceptionalHours(t *testing.T) {
 
 	ctx, tx := resetTestData(t)
-	
+
 	// Monday 2026-03-16 is normally CLOSED. Add exceptional hours: 10:00-16:00.
 	// Also add a blocker at 12:00-13:00.
 	// First create the exceptional group
@@ -2124,7 +2123,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_Admin_ExceptionalHours(t *test
 func TestScheduling_GetAvailableHours_WithBlocker_NonAdmin_ClosedDay(t *testing.T) {
 
 	ctx, tx := resetTestData(t)
-	
+
 	// Sunday 2026-03-22 closed, blocker at 10:00-11:00
 	blockerTime := time.Date(2026, 3, 22, 10, 0, 0, 0, time.UTC)
 	tx.Exec(ctx, `INSERT INTO time_blockers (start_time, duration_minutes, description, created_by) VALUES ($1, 60, 'Weekend Maintenance', NULL)`, blockerTime)
@@ -2163,7 +2162,7 @@ func TestScheduling_GetAvailableHours_WithBlocker_NonAdmin_ClosedDay(t *testing.
 func TestScheduling_GetAvailableHours_WithBlocker_NonAdmin_BookingAdjacent(t *testing.T) {
 
 	ctx, tx := resetTestData(t)
-	
+
 	bookingStart := time.Date(2026, 3, 17, 10, 0, 0, 0, time.UTC)
 	bookingEnd := bookingStart.Add(60 * time.Minute)
 	userID, err := fixtures.CreateTestUser(tx)
@@ -2417,7 +2416,7 @@ func TestNormalizeTime_Regression_RealWorldFormats(t *testing.T) {
 // slots from each affected day.
 func TestScheduling_GetAvailableHours_CrossDayBlocker(t *testing.T) {
 	ctx, tx := resetTestData(t)
-	
+
 	// Use Tue 2026-03-17 and Wed 2026-03-18 — both open days
 	_, tueEnd, tueOpen := getWorkingHoursForDate(t, ctx, "2026-03-17")
 	_, _, wedOpen := getWorkingHoursForDate(t, ctx, "2026-03-18")
diff --git a/backend/handlers/scheduling/testmain_test.go b/backend/handlers/scheduling/testmain_test.go
index e253dfa..6414141 100644
--- a/backend/handlers/scheduling/testmain_test.go
+++ b/backend/handlers/scheduling/testmain_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package scheduling
 
diff --git a/backend/handlers/scheduling/time_blockers_test.go b/backend/handlers/scheduling/time_blockers_test.go
index 0fd9d45..b59d3ba 100644
--- a/backend/handlers/scheduling/time_blockers_test.go
+++ b/backend/handlers/scheduling/time_blockers_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package scheduling
 
@@ -430,7 +429,6 @@ func TestGetTimeBlockersInRange(t *testing.T) {
 		t.Fatalf("failed to create blockers: %v", err)
 	}
 
-
 	// Query range that includes blocker1 and blocker2 but not blocker3
 	start := time.Date(2026, 3, 1, 0, 0, 0, 0, time.UTC)
 	end := time.Date(2026, 3, 16, 23, 59, 59, 0, time.UTC)
@@ -468,7 +466,6 @@ func TestGetTimeBlockersInRange_Empty(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-	
 	// Create a blocker
 	blockerTime := time.Date(2026, 3, 15, 10, 0, 0, 0, time.UTC)
 	_, err := tx.Exec(ctx, `
@@ -479,7 +476,6 @@ func TestGetTimeBlockersInRange_Empty(t *testing.T) {
 		t.Fatalf("failed to create blocker: %v", err)
 	}
 
-
 	// Query range with no blockers
 	start := time.Date(2026, 4, 1, 0, 0, 0, 0, time.UTC)
 	end := time.Date(2026, 4, 30, 23, 59, 59, 0, time.UTC)
@@ -514,7 +510,6 @@ func TestGetTimeBlockersInRange_IncludesRecurring(t *testing.T) {
 		t.Fatalf("failed to create blockers: %v", err)
 	}
 
-
 	// Query range: March 1-31, 2026
 	start := time.Date(2026, 3, 1, 0, 0, 0, 0, time.UTC)
 	end := time.Date(2026, 3, 31, 23, 59, 59, 0, time.UTC)
@@ -559,7 +554,6 @@ func TestCleanupOldReservations(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-	
 	// Create fixture users for the test
 	oldUserID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -666,7 +660,6 @@ func TestCleanupOldReservations_AdminWalkIn(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-	
 	// Create old walk-in reservation (>15 min old)
 	oldTime := clock.Now().Add(-16 * time.Minute)
 	_, err := tx.Exec(ctx, `
@@ -722,7 +715,6 @@ func TestCleanupOldReservations_AdminCallIn(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-	
 	// Create old call-in reservation (>15 min old)
 	oldTime := clock.Now().Add(-16 * time.Minute)
 	_, err := tx.Exec(ctx, `
@@ -778,7 +770,6 @@ func TestCleanupOldReservations_MixedTypes(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-	
 	// Create old user reservation (>1 hour old)
 	oldUserTime := clock.Now().Add(-2 * time.Hour)
 	_, err := tx.Exec(ctx, `
@@ -925,7 +916,6 @@ func TestGetTimeBlockersInRange_IncludesReservations(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-	
 	// Create a regular blocker for tomorrow at 10:00
 	tomorrow := clock.Now().Add(24 * time.Hour)
 	blockerTime := time.Date(tomorrow.Year(), tomorrow.Month(), tomorrow.Day(), 10, 0, 0, 0, time.UTC)
@@ -1130,7 +1120,6 @@ func TestAnonymizeStaleGuestAccounts_Exactly6Months(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	// Create guest user
 	guestID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -1183,7 +1172,6 @@ func TestAnonymizeStaleGuestAccounts_ActiveBooking_Skipped(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	// Create guest user
 	guestID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -1240,7 +1228,6 @@ func TestAnonymizeStaleGuestAccounts_NoBookings(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	// Create guest user with no bookings
 	guestID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -1280,7 +1267,6 @@ func TestCleanupExpiredFinancialRecords_PaymentOlderThan7Years(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
@@ -1363,7 +1349,6 @@ func TestCleanupExpiredFinancialRecords_AnonUserWithin1YearBuffer(t *testing.T)
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	guestID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
@@ -1434,7 +1419,6 @@ func TestCleanupExpiredFinancialRecords_PaymentOlderThan9Years(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
@@ -1502,7 +1486,6 @@ func TestCleanupExpiredFinancialRecords_AggregationCorrectTotals(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
@@ -1601,7 +1584,6 @@ func TestCleanupExpiredFinancialRecords_Idempotent(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
@@ -1701,7 +1683,6 @@ func TestCleanupExpiredFinancialRecords_ActiveUserWithin7Years(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
@@ -1763,7 +1744,6 @@ func TestCleanupExpiredFinancialRecords_AnonUserBothThresholdsElapsed(t *testing
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	guestID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
@@ -1839,7 +1819,6 @@ func TestCleanupExpiredFinancialRecords_RefundAggregatedAndDeleted(t *testing.T)
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
@@ -1934,7 +1913,6 @@ func TestAnonymizeStaleGuestAccounts(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	// Guest 1: last booking 7 months ago — should be anonymized
 	guest1ID, _ := fixtures.CreateTestUser(tx)
 	tx.Exec(ctx, `UPDATE users SET account_role = 'guest' WHERE id = $1`, guest1ID)
@@ -2002,7 +1980,6 @@ func TestCleanupOldReservations_EditRequest(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-	
 	// Create old edit_request reservation (>24 hours old)
 	oldTime := clock.Now().Add(-25 * time.Hour)
 	_, err := tx.Exec(ctx, `
@@ -2056,7 +2033,6 @@ func TestCleanupExpiredDeposits_ExpiredConfirmed(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
@@ -2118,7 +2094,6 @@ func TestCleanupExpiredDeposits_ExpiredPending(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
@@ -2182,7 +2157,6 @@ func TestCleanupExpiredDeposits_PaidDepositPreserved(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
@@ -2251,7 +2225,6 @@ func TestCleanupExpiredDeposits_FutureDeadlinePreserved(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
 		t.Fatalf("failed to create user: %v", err)
@@ -2313,7 +2286,6 @@ func TestCleanupExpiredGiftCards(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	// Make account_id nullable for this test — CleanupExpiredGiftCards inserts NULL
 	// for unredeemed gift cards (no user account to reference).
 	_, err := tx.Exec(ctx, `ALTER TABLE gift_card_expired_balances ALTER COLUMN account_id DROP NOT NULL`)
@@ -2385,7 +2357,6 @@ func TestCleanupExpiredGiftCards_SkipRecentlyUsed(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	// Make account_id nullable for this test — CleanupExpiredGiftCards inserts NULL
 	// for unredeemed gift cards (no user account to reference).
 	_, err := tx.Exec(ctx, `ALTER TABLE gift_card_expired_balances ALTER COLUMN account_id DROP NOT NULL`)
@@ -2437,7 +2408,6 @@ func TestCleanupExpiredGiftCards_SkipRedeemed(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	// Make account_id nullable for this test — CleanupExpiredGiftCards inserts NULL
 	// for unredeemed gift cards (no user account to reference). Even though this
 	// card is redeemed, the function may also match other cards; ensure schema allows it.
@@ -2498,7 +2468,6 @@ func TestCleanupIdleAccounts_WithBalance(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	// Create a user
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -2567,7 +2536,6 @@ func TestCleanupIdleAccounts_NoBalance(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	// Create a user
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -2603,7 +2571,6 @@ func TestCleanupIdleAccounts_SkipActive(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	// Create a user with recent last_login
 	userID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -2639,7 +2606,6 @@ func TestCleanupIdleAccounts_SkipAdminGuest(t *testing.T) {
 	t.Parallel()
 	ctx, tx := resetTestData(t)
 
-
 	// Create admin user with old last_login
 	adminID, err := fixtures.CreateTestUser(tx)
 	if err != nil {
@@ -2799,7 +2765,7 @@ func TestCleanupOldIdempotencyKeys_ClearsOldPayments(t *testing.T) {
 }
 
 func TestCleanupOldIdempotencyKeys_ClearsOldTillSales(t *testing.T) {
-	
+
 	ctx, tx := resetTestData(t)
 
 	// Create an admin user for till_sales.created_by
diff --git a/backend/handlers/services/services.go b/backend/handlers/services/services.go
index f46dc31..21e7f43 100644
--- a/backend/handlers/services/services.go
+++ b/backend/handlers/services/services.go
@@ -4,12 +4,12 @@ import (
 	"context"
 	"crussell/clock"
 	"crussell/db"
-	"github.com/jackc/pgx/v5"
 	"crussell/internal/validators"
 	"crussell/mw"
 	"database/sql"
 	"encoding/json"
 	"errors"
+	"github.com/jackc/pgx/v5"
 	"net/http"
 	"time"
 
@@ -84,7 +84,7 @@ func ToggleService(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.WriteHeader(http.StatusOK)
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"message": "Service toggled successfully",
 		"id":      serviceID,
 	})
@@ -247,7 +247,7 @@ func DeleteServiceHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.WriteHeader(http.StatusOK)
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"message": "Service deleted successfully",
 		"id":      serviceID,
 	})
@@ -305,7 +305,6 @@ func ServicesHandler(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 
-	
 		w.WriteHeader(http.StatusOK)
 
 		if services == nil {
@@ -402,7 +401,6 @@ func ServicesHandler(w http.ResponseWriter, r *http.Request) {
 	// Combine: eligible + ineligible
 	services = append(services, ineligibleServices...)
 
-
 	w.WriteHeader(http.StatusOK)
 
 	if services == nil {
@@ -509,7 +507,6 @@ func ServicesEligibleForUserHandler(w http.ResponseWriter, r *http.Request) {
 	// Sort and combine: valid first, then grayed out
 	services = append(services, grayedOutServices...)
 
-
 	w.WriteHeader(http.StatusOK)
 
 	if services == nil {
diff --git a/backend/handlers/services/services_test.go b/backend/handlers/services/services_test.go
index c2217e3..facb28b 100644
--- a/backend/handlers/services/services_test.go
+++ b/backend/handlers/services/services_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 // Package services contains tests for service listing and eligibility endpoints.
 //
@@ -22,8 +21,8 @@ import (
 	"testing"
 
 	"crussell/db"
-	"crussell/testutils"
 	"crussell/handlers/user"
+	"crussell/testutils"
 
 	"github.com/go-chi/chi/v5"
 )
diff --git a/backend/handlers/services/testmain_test.go b/backend/handlers/services/testmain_test.go
index 2a9e9a9..9d4d030 100644
--- a/backend/handlers/services/testmain_test.go
+++ b/backend/handlers/services/testmain_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package services
 
diff --git a/backend/handlers/today/testmain_test.go b/backend/handlers/today/testmain_test.go
index d785650..bd38b7f 100644
--- a/backend/handlers/today/testmain_test.go
+++ b/backend/handlers/today/testmain_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package today
 
diff --git a/backend/handlers/today/today.go b/backend/handlers/today/today.go
index 612dfac..e875b54 100644
--- a/backend/handlers/today/today.go
+++ b/backend/handlers/today/today.go
@@ -10,8 +10,8 @@ import (
 	"strings"
 	"time"
 
-	"crussell/db"
 	"crussell/clock"
+	"crussell/db"
 	"github.com/jackc/pgx/v5"
 )
 
@@ -31,11 +31,11 @@ type ServiceInfo struct {
 }
 
 type UserInfo struct {
-	ID               string  `json:"id"`
-	FullName         string  `json:"full_name"`
-	Phone            *string `json:"phone,omitempty"`
-	Email            *string `json:"email,omitempty"`
-	ProfilePicURL    *string `json:"profile_pic_url,omitempty"`
+	ID                string  `json:"id"`
+	FullName          string  `json:"full_name"`
+	Phone             *string `json:"phone,omitempty"`
+	Email             *string `json:"email,omitempty"`
+	ProfilePicURL     *string `json:"profile_pic_url,omitempty"`
 	PreviousFirstName *string `json:"previous_first_name,omitempty"`
 	PreviousLastName  *string `json:"previous_last_name,omitempty"`
 }
@@ -552,7 +552,7 @@ func getClosingTime(r *http.Request, date time.Time) string {
 }
 
 // Helper function to fetch a single appointment with all details
-func fetchAppointment(r *http.Request, query string, args ...interface{}) (*AppointmentInfo, error) {
+func fetchAppointment(r *http.Request, query string, args ...any) (*AppointmentInfo, error) {
 	var bookingID string
 	var startTime time.Time
 	var status string
@@ -681,15 +681,15 @@ func fetchAppointment(r *http.Request, query string, args ...interface{}) (*Appo
 }
 
 type TodayAppointment struct {
-	ID               string   `json:"id"`
-	StartTime        string   `json:"start_time"`
-	Status           string   `json:"status"`
-	UserName         string   `json:"user_name"`
-	UserID           string   `json:"user_id"`
-	Services         []string `json:"services"`
-	DurationMinutes  int      `json:"duration_minutes"`
-	PreviousFirstName *string `json:"previous_first_name,omitempty"`
-	PreviousLastName  *string `json:"previous_last_name,omitempty"`
+	ID                string   `json:"id"`
+	StartTime         string   `json:"start_time"`
+	Status            string   `json:"status"`
+	UserName          string   `json:"user_name"`
+	UserID            string   `json:"user_id"`
+	Services          []string `json:"services"`
+	DurationMinutes   int      `json:"duration_minutes"`
+	PreviousFirstName *string  `json:"previous_first_name,omitempty"`
+	PreviousLastName  *string  `json:"previous_last_name,omitempty"`
 }
 
 type TodayAppointmentsResponse struct {
@@ -903,15 +903,15 @@ func GetTodayAppointmentsHandler(w http.ResponseWriter, r *http.Request) {
 }
 
 type PendingApproval struct {
-	ID               string   `json:"id"`
-	StartTime        string   `json:"start_time"`
-	UserID           string   `json:"user_id"`
-	UserName         string   `json:"user_name"`
-	PreviousFirstName *string `json:"previous_first_name,omitempty"`
-	PreviousLastName  *string `json:"previous_last_name,omitempty"`
-	Services         []string `json:"services"`
-	DurationMinutes  int      `json:"duration_minutes"`
-	CreatedAt        string   `json:"created_at"`
+	ID                string   `json:"id"`
+	StartTime         string   `json:"start_time"`
+	UserID            string   `json:"user_id"`
+	UserName          string   `json:"user_name"`
+	PreviousFirstName *string  `json:"previous_first_name,omitempty"`
+	PreviousLastName  *string  `json:"previous_last_name,omitempty"`
+	Services          []string `json:"services"`
+	DurationMinutes   int      `json:"duration_minutes"`
+	CreatedAt         string   `json:"created_at"`
 }
 
 type PendingApprovalsResponse struct {
diff --git a/backend/handlers/today/today_test.go b/backend/handlers/today/today_test.go
index beefba3..08571bb 100644
--- a/backend/handlers/today/today_test.go
+++ b/backend/handlers/today/today_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package today
 
diff --git a/backend/handlers/user/customer_relationship_test.go b/backend/handlers/user/customer_relationship_test.go
index 7620f9e..3dee265 100644
--- a/backend/handlers/user/customer_relationship_test.go
+++ b/backend/handlers/user/customer_relationship_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package user
 
diff --git a/backend/handlers/user/gdpr_test.go b/backend/handlers/user/gdpr_test.go
index 625d6b4..b1a7948 100644
--- a/backend/handlers/user/gdpr_test.go
+++ b/backend/handlers/user/gdpr_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package user
 
@@ -12,8 +11,8 @@ import (
 	"time"
 
 	"crussell/clock"
-	"crussell/testutils"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 	"crussell/testutils/jwt"
 )
@@ -1284,8 +1283,8 @@ func TestCleanupGDPRExportCache_Mixed(t *testing.T) {
 
 	gdprExportCacheMu.Lock()
 	gdprExportCache = map[string]*gdprCacheEntry{
-		"user-expired": {expiresAt: clock.Now().Add(-2 * time.Hour)},
-		"user-valid":   {expiresAt: clock.Now().Add(2 * time.Hour)},
+		"user-expired":  {expiresAt: clock.Now().Add(-2 * time.Hour)},
+		"user-valid":    {expiresAt: clock.Now().Add(2 * time.Hour)},
 		"user-expired2": {expiresAt: clock.Now().Add(-30 * time.Minute)},
 	}
 	gdprExportCacheMu.Unlock()
diff --git a/backend/handlers/user/guest.go b/backend/handlers/user/guest.go
index 92d4862..a2f89e9 100644
--- a/backend/handlers/user/guest.go
+++ b/backend/handlers/user/guest.go
@@ -136,7 +136,6 @@ func CreateGuestUserHandler(w http.ResponseWriter, r *http.Request) {
 
 	// Note: We intentionally don't sync to CardDAV - guests don't need calendar contacts
 
-
 	w.WriteHeader(http.StatusCreated)
 	json.NewEncoder(w).Encode(CreateGuestUserResponse{ID: userID, Role: "guest"})
 }
@@ -192,8 +191,7 @@ func CheckEmailHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"suggestion": suggestion,
 	})
 }
diff --git a/backend/handlers/user/guest_test.go b/backend/handlers/user/guest_test.go
index 6a832bb..4657f0c 100644
--- a/backend/handlers/user/guest_test.go
+++ b/backend/handlers/user/guest_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package user
 
diff --git a/backend/handlers/user/patch_tests_test.go b/backend/handlers/user/patch_tests_test.go
index 50ce5ca..899e21d 100644
--- a/backend/handlers/user/patch_tests_test.go
+++ b/backend/handlers/user/patch_tests_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package user
 
@@ -10,8 +9,8 @@ import (
 	"strings"
 	"testing"
 
-	"crussell/testutils"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 
 	"github.com/go-chi/chi/v5"
@@ -174,5 +173,3 @@ func TestDeletePatchTest_InvalidTestID(t *testing.T) {
 		t.Errorf("expected 404 for invalid test ID, got %d", w.Code)
 	}
 }
-
-
diff --git a/backend/handlers/user/profile.go b/backend/handlers/user/profile.go
index a17b71a..5fcdab5 100644
--- a/backend/handlers/user/profile.go
+++ b/backend/handlers/user/profile.go
@@ -21,14 +21,14 @@ import (
 	"golang.org/x/text/cases"
 	"golang.org/x/text/language"
 
-	"crussell/db"
 	"crussell/clock"
-	"github.com/jackc/pgx/v5"
+	"crussell/db"
 	"crussell/handlers/auth"
 	"crussell/internal/images"
 	"crussell/internal/s3"
 	"crussell/internal/validators"
 	"crussell/mw"
+	"github.com/jackc/pgx/v5"
 )
 
 func getEnv(key, fallback string) string {
@@ -41,19 +41,19 @@ func getEnv(key, fallback string) string {
 var titleCaser = cases.Title(language.English)
 
 type UserProfile struct {
-	ID               string  `json:"id"`
-	Email            string  `json:"email"`
-	FirstName        string  `json:"firstName"`
-	LastName         string  `json:"lastName"`
-	Phone            *string `json:"phone,omitempty"`
-	DateOfBirth      *string `json:"dateOfBirth,omitempty"`
-	Role             string  `json:"role"`
-	LoyaltyStamps    int     `json:"loyaltyStamps"`
-	ReferralCode     string  `json:"referralCode"`
-	ReferralCodeUses int     `json:"referralCodeUses"`
-	ReferralSavings  float64 `json:"referralSavings"`
-	ProfilePicURL    *string `json:"profilePicUrl,omitempty"`
-	DepositsRequired int     `json:"deposits_required"`
+	ID                string  `json:"id"`
+	Email             string  `json:"email"`
+	FirstName         string  `json:"firstName"`
+	LastName          string  `json:"lastName"`
+	Phone             *string `json:"phone,omitempty"`
+	DateOfBirth       *string `json:"dateOfBirth,omitempty"`
+	Role              string  `json:"role"`
+	LoyaltyStamps     int     `json:"loyaltyStamps"`
+	ReferralCode      string  `json:"referralCode"`
+	ReferralCodeUses  int     `json:"referralCodeUses"`
+	ReferralSavings   float64 `json:"referralSavings"`
+	ProfilePicURL     *string `json:"profilePicUrl,omitempty"`
+	DepositsRequired  int     `json:"deposits_required"`
 	PreviousFirstName *string `json:"previousFirstName,omitempty"`
 	PreviousLastName  *string `json:"previousLastName,omitempty"`
 }
@@ -103,15 +103,15 @@ type SocialLogin struct {
 }
 
 type UserListItem struct {
-	ID               string    `json:"id"`
-	FullName         string    `json:"fullName"`
-	Email            *string   `json:"email,omitempty"`
-	Phone            *string   `json:"phone,omitempty"`
-	AccountRole      string    `json:"account_role"`
-	CreatedAt        time.Time `json:"created_at"`
-	PreviousFirstName *string  `json:"previousFirstName,omitempty"`
-	PreviousLastName  *string  `json:"previousLastName,omitempty"`
-	CompletedCount   int       `json:"completed_count"`
+	ID                string    `json:"id"`
+	FullName          string    `json:"fullName"`
+	Email             *string   `json:"email,omitempty"`
+	Phone             *string   `json:"phone,omitempty"`
+	AccountRole       string    `json:"account_role"`
+	CreatedAt         time.Time `json:"created_at"`
+	PreviousFirstName *string   `json:"previousFirstName,omitempty"`
+	PreviousLastName  *string   `json:"previousLastName,omitempty"`
+	CompletedCount    int       `json:"completed_count"`
 }
 
 type UserListResponse struct {
@@ -511,7 +511,7 @@ func ListAdminUsersHandler(w http.ResponseWriter, r *http.Request) {
     `
 
 	var listQuery string
-	var listArgs []interface{}
+	var listArgs []any
 
 	if searchTerm != "" {
 		searchPattern := "%" + searchTerm + "%"
@@ -520,7 +520,7 @@ func ListAdminUsersHandler(w http.ResponseWriter, r *http.Request) {
             WHERE (u.fn ILIKE $1 OR u.email ILIKE $1 OR u.phone ILIKE $1)
         ) sub`
 
-		listArgs = []interface{}{searchPattern}
+		listArgs = []any{searchPattern}
 
 		if cursorStr != "" {
 			cursorCount, cursorCreatedAt, cursorID, err := validators.ParseCursor3(cursorStr)
diff --git a/backend/handlers/user/profile_test.go b/backend/handlers/user/profile_test.go
index 20919f6..6df411b 100644
--- a/backend/handlers/user/profile_test.go
+++ b/backend/handlers/user/profile_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package user
 
@@ -25,8 +24,8 @@ import (
 	"net/http/httptest"
 	"testing"
 
-	"crussell/testutils"
 	"crussell/mw"
+	"crussell/testutils"
 	"crussell/testutils/fixtures"
 	"crussell/testutils/jwt"
 )
diff --git a/backend/handlers/user/testmain_test.go b/backend/handlers/user/testmain_test.go
index 169b90d..ccc4cec 100644
--- a/backend/handlers/user/testmain_test.go
+++ b/backend/handlers/user/testmain_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package user
 
diff --git a/backend/handlers/webhooks/webhooks_test.go b/backend/handlers/webhooks/webhooks_test.go
index 6a4d1eb..552cb97 100644
--- a/backend/handlers/webhooks/webhooks_test.go
+++ b/backend/handlers/webhooks/webhooks_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package webhooks
 
@@ -194,7 +193,7 @@ func TestHandleSquareWebhook_BodyTooLarge(t *testing.T) {
 }
 
 func TestHandleSquareWebhook_ValidSignatureWithEnvKey(t *testing.T) {
-	
+
 	body := []byte(`{"type":"payment.updated","event_id":"evt_1"}`)
 	key := "env-signing-key"
 	notificationURL := "http://localhost:8080/webhooks/square"
@@ -213,7 +212,7 @@ func TestHandleSquareWebhook_ValidSignatureWithEnvKey(t *testing.T) {
 }
 
 func TestHandleSquareWebhook_InvalidSignatureWithEnvKey(t *testing.T) {
-	
+
 	body := []byte(`{"type":"payment.updated","event_id":"evt_1"}`)
 
 	t.Setenv("SQUARE_WEBHOOK_SIGNATURE_KEY", "env-signing-key")
@@ -225,7 +224,7 @@ func TestHandleSquareWebhook_InvalidSignatureWithEnvKey(t *testing.T) {
 }
 
 func TestHandleSquareWebhook_NoSignatureWhenKeySet(t *testing.T) {
-	
+
 	body := []byte(`{"type":"payment.updated","event_id":"evt_1"}`)
 
 	t.Setenv("SQUARE_WEBHOOK_SIGNATURE_KEY", "env-signing-key")
@@ -238,7 +237,7 @@ func TestHandleSquareWebhook_NoSignatureWhenKeySet(t *testing.T) {
 }
 
 func TestHandleSquareWebhook_SignatureSkippedWhenKeyEmpty(t *testing.T) {
-	
+
 	t.Setenv("SQUARE_WEBHOOK_SIGNATURE_KEY", "")
 
 	body := []byte(`{"type":"payment.updated","event_id":"evt_1"}`)
diff --git a/backend/internal/dav/service_dev.go b/backend/internal/dav/service_dev.go
index 3d4d7a5..509aebe 100644
--- a/backend/internal/dav/service_dev.go
+++ b/backend/internal/dav/service_dev.go
@@ -1,5 +1,4 @@
 //go:build dev
-// +build dev
 
 package dav
 
diff --git a/backend/internal/dav/service_prod.go b/backend/internal/dav/service_prod.go
index 204c387..84ad4cc 100644
--- a/backend/internal/dav/service_prod.go
+++ b/backend/internal/dav/service_prod.go
@@ -1,5 +1,4 @@
 //go:build !dev
-// +build !dev
 
 package dav
 
diff --git a/backend/internal/dav/shared.go b/backend/internal/dav/shared.go
index 275ad08..c8f299f 100644
--- a/backend/internal/dav/shared.go
+++ b/backend/internal/dav/shared.go
@@ -1,8 +1,8 @@
 package dav
 
 import (
-	"crussell/clock"
 	"context"
+	"crussell/clock"
 	"fmt"
 	"strings"
 	"time"
@@ -131,7 +131,7 @@ func (s *BaseService) ListRecentContacts(days int) ([]Contact, error) {
 // Helper Methods
 // ============================================================================
 
-func (s *BaseService) queryEventsWithContacts(query string, args ...interface{}) ([]CalendarEvent, error) {
+func (s *BaseService) queryEventsWithContacts(query string, args ...any) ([]CalendarEvent, error) {
 	rows, err := s.db.Query(context.Background(), query, args...)
 	if err != nil {
 		return nil, err
@@ -155,7 +155,7 @@ func (s *BaseService) queryEventsWithContacts(query string, args ...interface{})
 
 func extractContactURIsFromICalendar(icalData string) []string {
 	var uris []string
-	for _, line := range strings.Split(icalData, "\n") {
+	for line := range strings.SplitSeq(icalData, "\n") {
 		line = strings.TrimSpace(line)
 		if strings.HasPrefix(line, "ATTENDEE") {
 			parts := strings.Split(line, ":")
diff --git a/backend/internal/dav/types.go b/backend/internal/dav/types.go
index ccb848e..dd55f29 100644
--- a/backend/internal/dav/types.go
+++ b/backend/internal/dav/types.go
@@ -3,6 +3,7 @@ package dav
 import (
 	"crussell/clock"
 	"fmt"
+	"strings"
 	"time"
 )
 
@@ -102,9 +103,9 @@ func GenerateICalEvent(input EventInput) string {
 	}
 
 	// Build attendees section
-	attendees := ""
+	var attendees strings.Builder
 	for _, contactURI := range input.ContactURIs {
-		attendees += fmt.Sprintf("ATTENDEE;CN=%s:%s\n", contactURI, contactURI)
+		attendees.WriteString(fmt.Sprintf("ATTENDEE;CN=%s:%s\n", contactURI, contactURI))
 	}
 
 	ical := fmt.Sprintf(`BEGIN:VCALENDAR
@@ -127,7 +128,7 @@ END:VCALENDAR`, uid, dtstamp, dtstart, dtend,
 		escapeICalText(input.Summary),
 		escapeICalText(input.Description),
 		escapeICalText(input.Location),
-		attendees)
+		attendees.String())
 
 	return ical
 }
@@ -164,13 +165,13 @@ func escapeICalText(text string) string {
 }
 
 func replaceAll(s, old, new string) string {
-	result := ""
+	var result strings.Builder
 	for _, char := range s {
 		if string(char) == old {
-			result += new
+			result.WriteString(new)
 		} else {
-			result += string(char)
+			result.WriteString(string(char))
 		}
 	}
-	return result
+	return result.String()
 }
diff --git a/backend/internal/images/validate_test.go b/backend/internal/images/validate_test.go
index 2ed4d6d..e835c09 100644
--- a/backend/internal/images/validate_test.go
+++ b/backend/internal/images/validate_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package images
 
diff --git a/backend/internal/s3/s3.go b/backend/internal/s3/s3.go
index 567da22..fa3556b 100644
--- a/backend/internal/s3/s3.go
+++ b/backend/internal/s3/s3.go
@@ -1,5 +1,4 @@
 //go:build !dev
-// +build !dev
 
 package s3
 
diff --git a/backend/internal/s3/s3_dev.go b/backend/internal/s3/s3_dev.go
index 3aeb712..1703b68 100644
--- a/backend/internal/s3/s3_dev.go
+++ b/backend/internal/s3/s3_dev.go
@@ -1,5 +1,4 @@
 //go:build dev
-// +build dev
 
 package s3
 
diff --git a/backend/internal/square/square.go b/backend/internal/square/square.go
index e123d29..4da1a17 100644
--- a/backend/internal/square/square.go
+++ b/backend/internal/square/square.go
@@ -1,5 +1,4 @@
 //go:build !dev
-// +build !dev
 
 package square
 
diff --git a/backend/internal/square/square_dev.go b/backend/internal/square/square_dev.go
index a2979df..2e9a969 100644
--- a/backend/internal/square/square_dev.go
+++ b/backend/internal/square/square_dev.go
@@ -1,11 +1,10 @@
 //go:build dev
-// +build dev
 
 package square
 
 import (
-	"crussell/clock"
 	"context"
+	"crussell/clock"
 	"fmt"
 	"log"
 	"os"
diff --git a/backend/internal/square/square_dev_test.go b/backend/internal/square/square_dev_test.go
index 15d9dbf..b23971e 100644
--- a/backend/internal/square/square_dev_test.go
+++ b/backend/internal/square/square_dev_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package square
 
diff --git a/backend/internal/validators/email.go b/backend/internal/validators/email.go
index 54a6cb5..1b70dc7 100644
--- a/backend/internal/validators/email.go
+++ b/backend/internal/validators/email.go
@@ -30,11 +30,11 @@ func ValidateEmail(email string) error {
 
 // NormalizeGiftCardCode strips non-alphanumeric characters and upper-cases the code.
 func NormalizeGiftCardCode(code string) string {
-	clean := ""
+	var clean strings.Builder
 	for _, char := range code {
 		if (char >= 'a' && char <= 'z') || (char >= 'A' && char <= 'Z') || (char >= '0' && char <= '9') {
-			clean += string(char)
+			clean.WriteString(string(char))
 		}
 	}
-	return clean
+	return clean.String()
 }
diff --git a/backend/internal/validators/email_test.go b/backend/internal/validators/email_test.go
index f716b60..d4f238b 100644
--- a/backend/internal/validators/email_test.go
+++ b/backend/internal/validators/email_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package validators
 
diff --git a/backend/main.go b/backend/main.go
index dfa29af..66963a5 100644
--- a/backend/main.go
+++ b/backend/main.go
@@ -25,8 +25,8 @@ import (
 	"crussell/db"
 	"crussell/mw"
 
-	authHandlers "crussell/handlers/auth"
 	"crussell/handlers/admin"
+	authHandlers "crussell/handlers/auth"
 	"crussell/handlers/bookings"
 	"crussell/handlers/notifications"
 	"crussell/handlers/payments"
@@ -68,9 +68,9 @@ func limitBody(limit int64) func(http.Handler) http.Handler {
 }
 
 const (
-	defaultBodyLimit    int64 = 1 * 1024 * 1024  // 1MB
-	uploadBodyLimit     int64 = 15 * 1024 * 1024 // 15MB
-	portfolioBodyLimit  int64 = 40 * 1024 * 1024 // 40MB (7 variants from 20MB source)
+	defaultBodyLimit   int64 = 1 * 1024 * 1024  // 1MB
+	uploadBodyLimit    int64 = 15 * 1024 * 1024 // 15MB
+	portfolioBodyLimit int64 = 40 * 1024 * 1024 // 40MB (7 variants from 20MB source)
 )
 
 // nColor / bColor — Chi-style ANSI colors for request logging.
@@ -78,11 +78,11 @@ type nColor string
 type bColor string
 
 var (
-	reset    = nColor(logutil.Reset)
-	nGreen   = nColor(logutil.Green)
-	nYellow  = nColor(logutil.Yellow)
-	nCyan    = nColor(logutil.Cyan)
-	nRed     = nColor(logutil.Red)
+	reset   = nColor(logutil.Reset)
+	nGreen  = nColor(logutil.Green)
+	nYellow = nColor(logutil.Yellow)
+	nCyan   = nColor(logutil.Cyan)
+	nRed    = nColor(logutil.Red)
 
 	bGreen   = bColor(logutil.BoldGreen)
 	bYellow  = bColor(logutil.BoldYellow)
@@ -153,7 +153,7 @@ func healthCheckHandler(w http.ResponseWriter, r *http.Request) {
 	} else {
 		w.WriteHeader(http.StatusOK)
 	}
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"status":   status,
 		"services": services,
 	})
@@ -440,15 +440,15 @@ func main() {
 				r.Post("/{id}/edit-requests/{request_id}/deny", bookings.AdminRejectEditRequestHandler)
 			})
 
-r.Route("/admin/users", func(r chi.Router) {
-			r.Get("/", user.ListAdminUsersHandler)
-			r.Get("/{id}", user.GetAdminUserHandler)
-			r.Get("/{id}/relationship", user.GetCustomerRelationshipHandler)
-			r.Get("/{id}/patch-tests/eligible", user.GetEligiblePatchTestServicesHandler)
-			r.Post("/{id}/patch-tests", user.AddPatchTestHandler)
-			r.Get("/{id}/giftcard-balance", payments.GetUserGiftCardBalanceAdmin)
-			r.Get("/{id}/payment-methods", payments.AdminGetUserPaymentMethods)
-		})
+			r.Route("/admin/users", func(r chi.Router) {
+				r.Get("/", user.ListAdminUsersHandler)
+				r.Get("/{id}", user.GetAdminUserHandler)
+				r.Get("/{id}/relationship", user.GetCustomerRelationshipHandler)
+				r.Get("/{id}/patch-tests/eligible", user.GetEligiblePatchTestServicesHandler)
+				r.Post("/{id}/patch-tests", user.AddPatchTestHandler)
+				r.Get("/{id}/giftcard-balance", payments.GetUserGiftCardBalanceAdmin)
+				r.Get("/{id}/payment-methods", payments.AdminGetUserPaymentMethods)
+			})
 
 			r.Route("/admin/today", func(r chi.Router) {
 				r.Get("/current-next", today.GetCurrentAndNextHandler)
@@ -456,11 +456,11 @@ r.Route("/admin/users", func(r chi.Router) {
 				r.Get("/pending-approvals", today.GetPendingApprovalsHandler)
 			})
 
-		r.Route("/admin/notifications", func(r chi.Router) {
-			r.Get("/", notifications.GetNotifications)
-			r.Get("/unread-count", notifications.GetUnreadCount)
-			r.Post("/{id}/acknowledge", notifications.AcknowledgeNotification)
-		})
+			r.Route("/admin/notifications", func(r chi.Router) {
+				r.Get("/", notifications.GetNotifications)
+				r.Get("/unread-count", notifications.GetUnreadCount)
+				r.Post("/{id}/acknowledge", notifications.AcknowledgeNotification)
+			})
 
 			r.Route("/admin/time-blockers", func(r chi.Router) {
 				r.Get("/", scheduling.ListTimeBlockers)
diff --git a/backend/main_test.go b/backend/main_test.go
index b8bd866..c9f0834 100644
--- a/backend/main_test.go
+++ b/backend/main_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package main
 
diff --git a/backend/mw/auth.go b/backend/mw/auth.go
index 18c32e6..2ff7bc9 100644
--- a/backend/mw/auth.go
+++ b/backend/mw/auth.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"log"
 	"net/http"
+	"slices"
 	"strings"
 
 	"crussell/auth"
@@ -77,13 +78,7 @@ func RequireRole(allowedRoles ...string) func(http.Handler) http.Handler {
 			}
 
 			// Check if user has one of the allowed roles
-			hasRole := false
-			for _, allowedRole := range allowedRoles {
-				if role == allowedRole {
-					hasRole = true
-					break
-				}
-			}
+			hasRole := slices.Contains(allowedRoles, role)
 
 			if !hasRole {
 				http.Error(w, "forbidden", http.StatusForbidden)
diff --git a/backend/mw/auth_test.go b/backend/mw/auth_test.go
index f0ccf1d..747f063 100644
--- a/backend/mw/auth_test.go
+++ b/backend/mw/auth_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package mw
 
diff --git a/backend/mw/contenttype_test.go b/backend/mw/contenttype_test.go
index 94fe45d..a20f5a1 100644
--- a/backend/mw/contenttype_test.go
+++ b/backend/mw/contenttype_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package mw
 
diff --git a/backend/mw/ratelimit.go b/backend/mw/ratelimit.go
index c1a7efe..a782056 100644
--- a/backend/mw/ratelimit.go
+++ b/backend/mw/ratelimit.go
@@ -1,5 +1,4 @@
 //go:build !dev
-// +build !dev
 
 package mw
 
diff --git a/backend/mw/ratelimit_dev.go b/backend/mw/ratelimit_dev.go
index 634704a..6de24ec 100644
--- a/backend/mw/ratelimit_dev.go
+++ b/backend/mw/ratelimit_dev.go
@@ -1,5 +1,4 @@
 //go:build dev
-// +build dev
 
 package mw
 
diff --git a/backend/mw/ratelimit_dev_test.go b/backend/mw/ratelimit_dev_test.go
index 1d47c0e..90ff6ca 100644
--- a/backend/mw/ratelimit_dev_test.go
+++ b/backend/mw/ratelimit_dev_test.go
@@ -1,5 +1,4 @@
 //go:build test && dev
-// +build test,dev
 
 package mw
 
diff --git a/backend/mw/ratelimit_prod_test.go b/backend/mw/ratelimit_prod_test.go
index c4ed514..f87f949 100644
--- a/backend/mw/ratelimit_prod_test.go
+++ b/backend/mw/ratelimit_prod_test.go
@@ -1,5 +1,4 @@
 //go:build test && !dev
-// +build test,!dev
 
 package mw
 
diff --git a/backend/mw/ratelimit_test.go b/backend/mw/ratelimit_test.go
index 3db7543..e5df86c 100644
--- a/backend/mw/ratelimit_test.go
+++ b/backend/mw/ratelimit_test.go
@@ -1,5 +1,4 @@
 //go:build test && !dev
-// +build test,!dev
 
 package mw
 
diff --git a/backend/testmain_test.go b/backend/testmain_test.go
index e9431aa..a97d384 100644
--- a/backend/testmain_test.go
+++ b/backend/testmain_test.go
@@ -1,5 +1,4 @@
 //go:build test
-// +build test
 
 package main