fix: replace silent json.Encode with error-logging pattern across all handlers

backend/handlers/scheduling/time-blockers.go

@@ -9,8 +9,8 @@ import (
 	"net/http"
 	"time"
 
-	"crussell/db"
 	"crussell/clock"
+	"crussell/db"
 	"crussell/internal/validators"
 	"crussell/mw"
 
@@ -113,7 +113,9 @@ func ListTimeBlockers(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.Header().Set("Content-Type", "application/json")
-	_ = json.NewEncoder(w).Encode(blockers)
+	if err := json.NewEncoder(w).Encode(blockers); err != nil {
+		log.Printf("Failed to encode JSON response: %v", err)
+	}
 }
 
 // --- Create Time Blocker ---
@@ -153,10 +155,10 @@ func CreateTimeBlocker(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	defer func() {
-    if err := tx.Rollback(r.Context()); err != nil && err.Error() != "tx is closed" {
-        slog.Error("failed to rollback transaction", "err", err)
-    }
-}()
+		if err := tx.Rollback(r.Context()); err != nil && err.Error() != "tx is closed" {
+			slog.Error("failed to rollback transaction", "err", err)
+		}
+	}()
 
 	// Insert the time blocker
 	var blocker TimeBlocker
@@ -180,7 +182,9 @@ func CreateTimeBlocker(w http.ResponseWriter, r *http.Request) {
 
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(http.StatusCreated)
-	_ = json.NewEncoder(w).Encode(blocker)
+	if err := json.NewEncoder(w).Encode(blocker); err != nil {
+		log.Printf("Failed to encode JSON response: %v", err)
+	}
 }
 
 // --- Delete Time Blocker ---
@@ -198,10 +202,10 @@ func DeleteTimeBlocker(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	defer func() {
-    if err := tx.Rollback(r.Context()); err != nil && err.Error() != "tx is closed" {
-        slog.Error("failed to rollback transaction", "err", err)
-    }
-}()
+		if err := tx.Rollback(r.Context()); err != nil && err.Error() != "tx is closed" {
+			slog.Error("failed to rollback transaction", "err", err)
+		}
+	}()
 
 	result, err := tx.Exec(r.Context(), `
 		DELETE FROM time_blockers WHERE id = $1
@@ -361,14 +365,14 @@ func CheckTimeBlockerOverlap(ctx context.Context, startTime, endTime time.Time,
 }
 
 // CleanupOldReservations deletes expired reservations:
-// - Logged-in (RESERVATION:user): older than 1 hour
-// - Anonymous (RESERVATION:anon): older than 10 minutes
-// - Admin walk-in (RESERVATION:admin:walkin:%): older than 15 minutes
-// - Admin call-in (RESERVATION:admin:callin:%): older than 15 minutes
-// - Edit request (RESERVATION:edit_request:%): older than 24 hours
-// - Payment in-flight (PAYMENT_IN_FLIGHT:%): TTL via duration_minutes column
-//   (AcquirePaymentLock sets duration_minutes = PaymentLockDuration = 5min and
-//   start_time = NOW(), so the condition evaluates to "cleanup after 5 minutes".
+//   - Logged-in (RESERVATION:user): older than 1 hour
+//   - Anonymous (RESERVATION:anon): older than 10 minutes
+//   - Admin walk-in (RESERVATION:admin:walkin:%): older than 15 minutes
+//   - Admin call-in (RESERVATION:admin:callin:%): older than 15 minutes
+//   - Edit request (RESERVATION:edit_request:%): older than 24 hours
+//   - Payment in-flight (PAYMENT_IN_FLIGHT:%): TTL via duration_minutes column
+//     (AcquirePaymentLock sets duration_minutes = PaymentLockDuration = 5min and
+//     start_time = NOW(), so the condition evaluates to "cleanup after 5 minutes".
 func CleanupOldReservations(ctx context.Context) (int, error) {
 	oneHourAgo := clock.Now().Add(-1 * time.Hour)
 	tenMinutesAgo := clock.Now().Add(-10 * time.Minute)
@@ -380,10 +384,10 @@ func CleanupOldReservations(ctx context.Context) (int, error) {
 		return 0, fmt.Errorf("failed to begin transaction: %w", err)
 	}
 	defer func() {
-    if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
-        slog.Error("failed to rollback transaction", "err", err)
-    }
-}()
+		if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
+			slog.Error("failed to rollback transaction", "err", err)
+		}
+	}()
 
 	tag, err := tx.Exec(ctx, `
 		DELETE FROM time_blockers
@@ -411,10 +415,10 @@ func AnonymizeStaleGuestAccounts(ctx context.Context) (int, error) {
 		return 0, fmt.Errorf("failed to begin transaction: %w", err)
 	}
 	defer func() {
-    if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
-        slog.Error("failed to rollback transaction", "err", err)
-    }
-}()
+		if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
+			slog.Error("failed to rollback transaction", "err", err)
+		}
+	}()
 
 	var totalRows int
 
@@ -507,10 +511,10 @@ func CleanupExpiredLoyaltyRedemptions(ctx context.Context) (int, error) {
 		return 0, fmt.Errorf("failed to begin transaction: %w", err)
 	}
 	defer func() {
-    if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
-        slog.Error("failed to rollback transaction", "err", err)
-    }
-}()
+		if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
+			slog.Error("failed to rollback transaction", "err", err)
+		}
+	}()
 
 	tag, err := tx.Exec(ctx, `
 		DELETE FROM loyalty_redemptions
@@ -555,10 +559,10 @@ func CleanupExpiredFinancialRecords(ctx context.Context) (int, error) {
 		return 0, fmt.Errorf("failed to begin transaction: %w", err)
 	}
 	defer func() {
-    if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
-        slog.Error("failed to rollback transaction", "err", err)
-    }
-}()
+		if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
+			slog.Error("failed to rollback transaction", "err", err)
+		}
+	}()
 
 	var totalRows int
 
@@ -584,7 +588,7 @@ func CleanupExpiredFinancialRecords(ctx context.Context) (int, error) {
 		LEFT JOIN bookings b ON p.booking_id = b.id
 		LEFT JOIN users u ON b.user_id = u.id
 		WHERE p.created_at < NOW() - INTERVAL '7 years'
-		` + retentionFilter + `
+		`+retentionFilter+`
 		GROUP BY DATE_TRUNC('month', p.created_at)::date
 		ON CONFLICT (month) DO UPDATE SET
 			total_payments     = financial_aggregates.total_payments + EXCLUDED.total_payments,
@@ -617,7 +621,7 @@ func CleanupExpiredFinancialRecords(ctx context.Context) (int, error) {
 		LEFT JOIN bookings b ON p.booking_id = b.id
 		LEFT JOIN users u ON b.user_id = u.id
 		WHERE p.created_at < NOW() - INTERVAL '7 years'
-		` + retentionFilter + `
+		`+retentionFilter+`
 		GROUP BY DATE_TRUNC('month', r.created_at)::date
 		ON CONFLICT (month) DO UPDATE SET
 			total_refunds = financial_aggregates.total_refunds + EXCLUDED.total_refunds
@@ -633,7 +637,7 @@ func CleanupExpiredFinancialRecords(ctx context.Context) (int, error) {
 		LEFT JOIN users u ON b.user_id = u.id
 		WHERE p.booking_id = b.id
 		  AND p.created_at < NOW() - INTERVAL '7 years'
-		` + retentionFilter + `
+		`+retentionFilter+`
 	`)
 	if err != nil {
 		return 0, fmt.Errorf("failed to delete expired payments: %w", err)
@@ -647,7 +651,7 @@ func CleanupExpiredFinancialRecords(ctx context.Context) (int, error) {
 		LEFT JOIN users u ON b.user_id = u.id
 		WHERE r.payment_id = p.id
 		  AND p.created_at < NOW() - INTERVAL '7 years'
-		` + retentionFilter + `
+		`+retentionFilter+`
 	`)
 	if err != nil {
 		return 0, fmt.Errorf("failed to delete expired refunds: %w", err)
@@ -671,10 +675,10 @@ func CleanupExpiredDeposits(ctx context.Context) (int, error) {
 		return 0, fmt.Errorf("failed to begin transaction: %w", err)
 	}
 	defer func() {
-    if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
-        slog.Error("failed to rollback transaction", "err", err)
-    }
-}()
+		if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
+			slog.Error("failed to rollback transaction", "err", err)
+		}
+	}()
 
 	// Collect all evicted booking IDs from both updates so we can notify
 	// and clean up in one pass instead of re-scanning via updated_at = NOW().
@@ -803,10 +807,10 @@ func CleanupExpiredGiftCards(ctx context.Context) (int, error) {
 		return 0, fmt.Errorf("failed to begin transaction: %w", err)
 	}
 	defer func() {
-    if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
-        slog.Error("failed to rollback transaction", "err", err)
-    }
-}()
+		if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
+			slog.Error("failed to rollback transaction", "err", err)
+		}
+	}()
 
 	rows, err := tx.Query(ctx, `
 		SELECT id, amount_remaining
@@ -905,10 +909,10 @@ func CleanupIdleAccounts(ctx context.Context) (int, error) {
 		return 0, fmt.Errorf("failed to begin transaction: %w", err)
 	}
 	defer func() {
-    if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
-        slog.Error("failed to rollback transaction", "err", err)
-    }
-}()
+		if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
+			slog.Error("failed to rollback transaction", "err", err)
+		}
+	}()
 
 	rowsWithBalance, err := tx.Query(ctx, `
 		SELECT u.id, COALESCE(b.balance, 0) as balance
@@ -1014,10 +1018,10 @@ func CleanupOldIdempotencyKeys(ctx context.Context) (int, error) {
 		return 0, fmt.Errorf("failed to begin transaction: %w", err)
 	}
 	defer func() {
-    if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
-        slog.Error("failed to rollback transaction", "err", err)
-    }
-}()
+		if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
+			slog.Error("failed to rollback transaction", "err", err)
+		}
+	}()
 
 	var totalRows int
 
@@ -1069,10 +1073,10 @@ func CleanupOldNameHistory(ctx context.Context) (int, error) {
 		return 0, fmt.Errorf("failed to begin transaction: %w", err)
 	}
 	defer func() {
-    if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
-        slog.Error("failed to rollback transaction", "err", err)
-    }
-}()
+		if err := tx.Rollback(ctx); err != nil && err.Error() != "tx is closed" {
+			slog.Error("failed to rollback transaction", "err", err)
+		}
+	}()
 
 	tag, err := tx.Exec(ctx, `
 		DELETE FROM name_history