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EnakPoint & EnakCoin PRD and tasks note what is superseded.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/constants/wallet.go

@@ -14,26 +14,23 @@ func IsValidWalletCurrency(currency string) bool {
 // Ledger row types. §8.1 of the PRD lists, per type, which currency it may use, which
 // way it moves the balance, and which reference it must carry.
 const (
-	WalletTxTypeEarn          = "EARN"
-	WalletTxTypeEarnReversal  = "EARN_REVERSAL"
-	WalletTxTypePayment       = "PAYMENT"
-	WalletTxTypePaymentRefund = "PAYMENT_REFUND"
-	WalletTxTypeExchangeOut   = "EXCHANGE_OUT"
-	WalletTxTypeExchangeIn    = "EXCHANGE_IN"
-	WalletTxTypeTransferOut   = "TRANSFER_OUT"
-	WalletTxTypeTransferIn    = "TRANSFER_IN"
-	WalletTxTypeGameSpend     = "GAME_SPEND"
-	WalletTxTypeExpire        = "EXPIRE"
-	WalletTxTypeAdjustment    = "ADJUSTMENT"
-	WalletTxTypeMigration     = "MIGRATION"
-	WalletTxTypeRewardRedeem  = "REWARD_REDEEM"
+	WalletTxTypeEarn         = "EARN"
+	WalletTxTypeEarnReversal = "EARN_REVERSAL"
+	WalletTxTypeExchangeOut  = "EXCHANGE_OUT"
+	WalletTxTypeExchangeIn   = "EXCHANGE_IN"
+	WalletTxTypeTransferOut  = "TRANSFER_OUT"
+	WalletTxTypeTransferIn   = "TRANSFER_IN"
+	WalletTxTypeGameSpend    = "GAME_SPEND"
+	WalletTxTypeExpire       = "EXPIRE"
+	WalletTxTypeAdjustment   = "ADJUSTMENT"
+	WalletTxTypeMigration    = "MIGRATION"
+	WalletTxTypeRewardRedeem = "REWARD_REDEEM"
 )
 
 // What a ledger row's reference_id points at: where the value came from for a
 // credit, or where it went for a debit.
 const (
 	WalletRefTypeOrder            = "ORDER"
-	WalletRefTypePayment          = "PAYMENT"
 	WalletRefTypeWalletTx         = "WALLET_TX"
 	WalletRefTypeGamePlay         = "GAME_PLAY"
 	WalletRefTypeLot              = "LOT"