Fix tip amount-change false dedup, wire BuyerEmail everywhere, clear ESLint errors

Money-moving fixes:
- Tip idempotency key regenerates when the tip amount changes after a failed
  attempt (all 3 tip flows). Cached key still reused on same-amount retry
  (dedup intact) and cleared on success/modal reset. Prevents silent
  under-charge when a user retries at a different amount.
- Till replay path returns actual till_sales.status (may be 'pending') instead
  of hardcoded 'completed' — no more misreported successful charge.
- BuyerEmail wired for CreateBookingPayment, gift card purchases, and till
  sales (saved_card + online_square), matching the tip flow. Email lookup
  errors logged, non-fatal.
- Till buyer-email errors now logged (was silently swallowed).
- on_the_house till top-up uses cached getIdempotencyKey() for retry-safe dedup
  (was fresh crypto.randomUUID()).

Test/validation fixes:
- Add TestPaymentFromSquare_* unit tests (else-branch + nil card details),
  build tag relaxed to 'test' so they run in the standard dev suite.
- Add TestValidateCardInfo table test (7 cases: both/either/neither/empty).
- Add TestCreateTillSale_TwoIdenticalCreateSales_BothSucceed regression test.
- Remove dead mock pre-registration in TestTipPayment_WithSavedCard.
- Correct misleading till regression-test comment.

ESLint cleanup (12 errors -> 0):
- Remove unused loadingCards in tip + pay-tip pages (dead assignments in
  loadSavedCards).
- Scoped eslint-disable for {@html} in CardBrandIcon (hardcoded brand SVGs).
- Remove dead confirmSaveDefaultHours + unused rescheduleVersion prop in
  WeeklySchedule (and its parent pass-through).
- Replace new Date() with SvelteDate in WeeklySchedule + BusinessHours.
- Fix each-block key in BusinessHours skeleton loader.
- Use void expression for reactivity-tracker reads in effects.

backend/handlers/payments/giftcards.go

@@ -999,12 +999,18 @@ func BuyGiftCard(w http.ResponseWriter, r *http.Request) {
 
 	// Step 2: DB transaction committed — safe to call Square now.
 	// If Square fails, the payment record stays 'pending' for manual retry.
+	var buyerEmail string
+	if err := db.Conn.QueryRow(ctx, `SELECT email FROM users WHERE id = $1`, userID).Scan(&buyerEmail); err != nil {
+		log.Printf("[SQUARE-PROD] Failed to resolve buyer email for user %s: %v (Square receipts will not be emailed)", userID, err)
+	}
+
 	paymentReq := square.CreatePaymentReq{
 		Amount:         req.Amount,
 		Currency:       "GBP",
 		SourceID:       sourceID,
 		IdempotencyKey: req.IdempotencyKey,
 		Note:           "Gift Card Purchase",
+		BuyerEmail:     buyerEmail,
 	}
 
 	paymentResult, err := SquareClient.CreatePayment(ctx, paymentReq)

backend/handlers/payments/handlers.go

@@ -2,6 +2,7 @@ package payments
 
 import (
 	"context"
+	"crypto/rand"
 	"crussell/clock"
 	"crussell/db"
 	"crussell/internal/square"
@@ -47,10 +48,11 @@ type RefundRequest struct {
 }
 
 type CreateTipPaymentRequest struct {
-	Amount       int64   `json:"amount" validate:"required,gt=0"`
-	CardID       *string `json:"card_id,omitempty"`
-	NewCardToken *string `json:"new_card_token,omitempty"`
-	SaveCard     bool    `json:"save_card"`
+	Amount         int64   `json:"amount" validate:"required,gt=0"`
+	CardID         *string `json:"card_id,omitempty"`
+	NewCardToken   *string `json:"new_card_token,omitempty"`
+	SaveCard       bool    `json:"save_card"`
+	IdempotencyKey string  `json:"idempotency_key,omitempty"`
 }
 
 type CheckoutResponse struct {
@@ -759,6 +761,12 @@ func CreateBookingPayment(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// Resolve buyer email for Square receipt delivery (failure is non-fatal).
+	var bookingBuyerEmail string
+	if err := db.Conn.QueryRow(r.Context(), `SELECT email FROM users WHERE id = $1`, userID).Scan(&bookingBuyerEmail); err != nil {
+		log.Printf("[SQUARE-PROD] Failed to resolve buyer email for user %s: %v (Square receipts will not be emailed)", userID, err)
+	}
+
 	// M8
 	// L5
 
@@ -980,6 +988,7 @@ func CreateBookingPayment(w http.ResponseWriter, r *http.Request) {
 		IdempotencyKey: req.IdempotencyKey,
 		ReferenceID:    bookingID,
 		Note:           req.PaymentType,
+		BuyerEmail:     bookingBuyerEmail,
 	}
 
 	paymentResult, err := SquareClient.CreatePayment(r.Context(), paymentReq)
@@ -1801,7 +1810,14 @@ func CreateTipPayment(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	idempotencyKey := bookingID + "-tip-" + strconv.FormatInt(req.Amount, 10)
+	// Idempotency key: prefer the client-supplied UUID (one per attempt, so
+	// two legitimate identical tips on the same booking don't collapse into
+	// one). Fall back to a unique key when absent — must NOT be derived from
+	// request fields alone (bookingID + amount would dedupe distinct tips).
+	idempotencyKey := req.IdempotencyKey
+	if idempotencyKey == "" {
+		idempotencyKey = uniqueTipKey()
+	}
 
 	// Resolve the card source ID — same pattern as CreateBookingPayment.
 	var sourceID string
@@ -2208,3 +2224,10 @@ func ReleasePaymentLock(w http.ResponseWriter, r *http.Request) {
 
 	w.WriteHeader(http.StatusNoContent)
 }
+
+// uniqueTipKey generates a unique idempotency key for tip payments where the
+// client did not supply one. Client-supplied UUIDs handle retry dedup; this
+// fallback only needs uniqueness so identical tips don't collapse.
+func uniqueTipKey() string {
+	return "tip-" + rand.Text()
+}

backend/handlers/payments/payments_test.go

@@ -15,7 +15,6 @@ import (
 
 	"crussell/clock"
 	"crussell/db"
-	"crussell/internal/square"
 	"crussell/mw"
 	"crussell/testutils"
 	"crussell/testutils/fixtures"
@@ -31,6 +30,38 @@ func makePaymentRequest(handler http.HandlerFunc, method, path string, body inte
 	return makePaymentAuthRequest(handler, method, path, body, token, "", ctx)
 }
 
+func TestValidateCardInfo(t *testing.T) {
+	empty := ""
+	cardID := "card_123"
+	token := "cnon:test"
+
+	tests := []struct {
+		name      string
+		cardID    *string
+		newToken  *string
+		wantError bool
+	}{
+		{"both set rejected", &cardID, &token, true},
+		{"card_id only ok", &cardID, nil, false},
+		{"token only ok", nil, &token, false},
+		{"neither set rejected", nil, nil, true},
+		{"empty card_id rejected", &empty, nil, true},
+		{"empty token rejected", nil, &empty, true},
+		{"both empty rejected", &empty, &empty, true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := ValidateCardInfo(tt.cardID, tt.newToken)
+			if tt.wantError {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+			}
+		})
+	}
+}
+
 func makePaymentAuthRequest(handler http.HandlerFunc, method, path string, body interface{}, token, userIDOverride string, ctx context.Context) *httptest.ResponseRecorder {
 	var req *http.Request
 	if body != nil {
@@ -1875,18 +1906,6 @@ func TestTipPayment_WithSavedCard(t *testing.T) {
 	_, err = tx.Exec(ctx, "UPDATE payments SET square_payment_id = $1 WHERE id = $2", squarePayID, payID)
 	require.NoError(t, err)
 
-	// Register the payment in the mock so the tip flow works.
-	mockClient, ok := SquareClient.(*square.MockClient)
-	require.True(t, ok, "SquareClient must be a MockClient for this test")
-	_, err = mockClient.CreatePayment(ctx, square.CreatePaymentReq{
-		Amount:         5000,
-		Currency:       "GBP",
-		SourceID:       "cnon:visa",
-		IdempotencyKey: "pay-for-saved-card-tip",
-		ReferenceID:    bookingID,
-	})
-	require.NoError(t, err)
-
 	// Create a saved card for this user.
 	var savedCardID string
 	err = tx.QueryRow(ctx, `

backend/handlers/payments/till.go

@@ -105,16 +105,17 @@ func CreateTillSale(w http.ResponseWriter, r *http.Request) {
 
 	// Idempotency check: if key provided, return existing sale if found
 	if req.IdempotencyKey != "" {
-		var existingID string
-		err := db.Conn.QueryRow(ctx, `SELECT id FROM till_sales WHERE idempotency_key = $1`, req.IdempotencyKey).Scan(&existingID)
+		var existingID, existingStatus string
+		err := db.Conn.QueryRow(ctx, `SELECT id, status FROM till_sales WHERE idempotency_key = $1`, req.IdempotencyKey).Scan(&existingID, &existingStatus)
 		if err == nil {
-			// Existing sale found — return it (idempotent)
+			// Existing sale found — return its ACTUAL status (may be 'pending'
+			// if a previous Square charge failed; must not report 'completed').
 			if err := json.NewEncoder(w).Encode(TillSaleResponse{
 				ID:            existingID,
 				ItemType:      req.ItemType,
 				TotalAmount:   req.Amount,
 				PaymentMethod: req.PaymentMethod,
-				Status:        "completed",
+				Status:        existingStatus,
 			}); err != nil {
 				log.Printf("Failed to encode JSON response: %v", err)
 			}
@@ -408,6 +409,18 @@ func CreateTillSale(w http.ResponseWriter, r *http.Request) {
 
 	// Step 2: DB transaction committed — safe to call Square now.
 	// If Square fails, the till_sale record stays 'pending' for manual retry.
+	// Resolve buyer email for Square receipt delivery (non-fatal if missing).
+	var buyerEmail string
+	if req.UserID != nil && *req.UserID != "" {
+		if err := db.Conn.QueryRow(ctx, `SELECT email FROM users WHERE id = $1`, *req.UserID).Scan(&buyerEmail); err != nil {
+			log.Printf("[SQUARE-PROD] Failed to resolve buyer email for user %s: %v (Square receipts will not be emailed)", *req.UserID, err)
+		}
+	}
+	if buyerEmail == "" {
+		if err := db.Conn.QueryRow(ctx, `SELECT email FROM users WHERE id = $1`, adminID).Scan(&buyerEmail); err != nil {
+			log.Printf("[SQUARE-PROD] Failed to resolve admin email for user %s: %v (Square receipts will not be emailed)", adminID, err)
+		}
+	}
 	if needsSquarePayment {
 		var paymentResult *square.PaymentResult
 		var squareErr error
@@ -419,6 +432,7 @@ func CreateTillSale(w http.ResponseWriter, r *http.Request) {
 				SourceID:       savedCardSqCardID,
 				IdempotencyKey: req.IdempotencyKey,
 				Note:           "Gift Card " + req.Action,
+				BuyerEmail:     buyerEmail,
 			}
 			paymentResult, squareErr = SquareClient.CreatePayment(ctx, paymentReq)
 		} else if req.PaymentMethod == "online_square" {
@@ -435,6 +449,7 @@ func CreateTillSale(w http.ResponseWriter, r *http.Request) {
 				SourceID:       cardOnFile.CardID,
 				IdempotencyKey: req.IdempotencyKey,
 				Note:           "Gift Card " + req.Action,
+				BuyerEmail:     buyerEmail,
 			}
 			paymentResult, squareErr = SquareClient.CreatePayment(ctx, paymentReq)
 		}

backend/handlers/payments/till_test.go

@@ -881,11 +881,10 @@ func TestCreateTillSale_CreateCash(t *testing.T) {
 	}
 }
 
-// TestCreateTillSale_TwoIdenticalCreateSales_BothSucceed is a regression test:
-// two identical keyless cash gift-card creations must BOTH return 201. The
-// idempotency-key fallback must be unique per request (not derived from request
-// fields, which are identical for the two sales) or the second sale would
-// collide on the till_sales idempotency_key UNIQUE constraint and return 500.
+// TestCreateTillSale_TwoIdenticalCreateSales_BothSucceed verifies that two
+// identical keyless cash gift-card creations both return 201. The idempotency-key
+// fallback must be unique per request so legitimate repeat sales don't collide
+// on the till_sales idempotency_key UNIQUE constraint.
 func TestCreateTillSale_TwoIdenticalCreateSales_BothSucceed(t *testing.T) {
 	t.Parallel()
 	_, tx := testutils.SetupTestTx(t)