feat(loyalty): remove paying with EnakPoint

EnakPoint can only be redeemed for vouchers now: it can no longer pay for
orders and is never cashed out (docs/enakgame-prd.md §3.2, EG-001,
EG-002). No order was ever paid with EnakPoint, so there is no data to
move.

Removed:
- POST /customer/wallet/payment-code, POST /customer/orders/:id/pay-with-points
  and GET /orders/:id/point-payment/preview, with their processors,
  repositories, services, handlers and tests.
- The point payment method type: paying, splitting and refunding with it,
  the outlet filter on the method list, and the system-method guard.
- points and payment_code on CreatePayment; points_used and point_value
  on payments; accepts_point_payment on the customer outlets.
- The outlet point_payment settings. A PUT that still sends them is
  rejected as an unknown field.
- The EnakPoint split in the payment method analytics.
- PAYMENT and PAYMENT_REFUND from the wallet type rules. Tests that used
  them as a generic EnakPoint debit use REWARD_REDEEM.
- The EnakPoint-paid part from the earning basis, which is
  subtotal − discount again.

Migration 000102 drops the trigger, the point methods and their index,
the payments columns, and the outlet settings, and restores the method
type CHECK without point. payments.payment_method_id is ON DELETE
RESTRICT, so it fails rather than lose a payment made with EnakPoint.

The integration docs list the removed endpoints and fields, and the
EnakPoint & EnakCoin PRD and tasks note what is superseded.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/models/payment.go

@@ -28,10 +28,8 @@ type Payment struct {
 }
 
 type CreatePaymentRequest struct {
-	OrderID           uuid.UUID `validate:"required"`
-	PaymentMethodID   uuid.UUID `validate:"required"`
-	Points            *int64
-	PaymentCode       *string
+	OrderID           uuid.UUID                       `validate:"required"`
+	PaymentMethodID   uuid.UUID                       `validate:"required"`
 	Amount            float64                         `validate:"required,min=0"`
 	TransactionID     *string                         `validate:"omitempty"`
 	SplitNumber       int                             `validate:"omitempty,min=1"`
@@ -62,9 +60,6 @@ type PaymentResponse struct {
 	SplitType         *string
 	SplitDescription  *string
 	RefundAmount      float64
-	// Set for a payment with EnakPoint.
-	PointsUsed        *int64
-	PointValue        *float64
 	RefundReason      *string
 	RefundedAt        *time.Time
 	RefundedBy        *uuid.UUID