fix(payments): stop doubling the pack size in buyer mail

Catalog titles already name the pack ("50 фишек"), so appending the chip count
produced "50 фишек — 50 фишек, 79.00 ₽". The letter now carries the title
exactly as the storefront shows it, then the price.

The tax receipt is unaffected: it states the quantity in the wording the tax
service wants, which is a separate surface with separate requirements.

backend/internal/payments/mynalog.go

@@ -125,7 +125,6 @@ type PurchaseMail struct {
 	OrderID     uuid.UUID
 	Origin      string
 	Title       string
-	Chips       int
 	AmountMinor int64
 	Currency    string
 	CreatedAt   time.Time
@@ -137,7 +136,6 @@ type ReceiptMail struct {
 	AccountID     uuid.UUID
 	ReceiptUUID   string
 	Title         string
-	Chips         int
 	AmountMinor   int64
 	Currency      string
 	OperationTime time.Time

backend/internal/payments/store_mynalog.go

@@ -476,7 +476,7 @@ func (s *Store) pendingPurchaseMails(ctx context.Context, limit int) ([]Purchase
 	rows, err := s.db.QueryContext(ctx, `
 		SELECT e.event_id, e.account_id, e.order_id, COALESCE(o.origin, ''),
 		       COALESCE(o.expected_amount, 0), COALESCE(o.currency, ''),
-		       COALESCE(p.title, ''), COALESCE((e.payload->>'chips')::int, 0), e.created_at
+		       COALESCE(p.title, ''), e.created_at
 		FROM payments.payment_events e
 		LEFT JOIN payments.orders o ON o.order_id = e.order_id
 		LEFT JOIN payments.product p ON p.product_id = o.product_id
@@ -495,7 +495,7 @@ func (s *Store) pendingPurchaseMails(ctx context.Context, limit int) ([]Purchase
 			orderID uuid.NullUUID
 		)
 		if err := rows.Scan(&m.EventID, &m.AccountID, &orderID, &m.Origin, &m.AmountMinor,
-			&m.Currency, &m.Title, &m.Chips, &m.CreatedAt); err != nil {
+			&m.Currency, &m.Title, &m.CreatedAt); err != nil {
 			return nil, fmt.Errorf("payments: scan purchase mail: %w", err)
 		}
 		m.OrderID = orderID.UUID
@@ -551,7 +551,7 @@ func (s *Store) pendingMyNalogMails(ctx context.Context, limit int, cancelled bo
 			&m.AmountMinor, &m.Currency, &m.OperationTime); err != nil {
 			return nil, fmt.Errorf("payments: scan receipt mail: %w", err)
 		}
-		m.Title, m.Chips = describeSnapshot(snapshot.String)
+		m.Title, _ = describeSnapshot(snapshot.String)
 		out = append(out, m)
 	}
 	if err := rows.Err(); err != nil {