feat(payment): implement change payment method (PATCH /payment-method)

- ChangePaymentMethodPayload + ChangePaymentMethodResult models
- ApiService.changePaymentMethod()
- PixPaymentContext gains storeId + order data for payment switch
- PaymentPixView: Trocar button opens ChangePaymentSheet with 3 options
- ChangePaymentSheet: Novo PIX (new QR), Cartão (saved or new), Pagar na Entrega
- ChangePaymentCardSheet + ChangePaymentNewCardView with same card masks/validation
- OrdersView/OrderEntryDestinationView: threaded appState binding

pedi-foods/Sources/PediFoods/Services/ApiCardModels.swift

@@ -65,3 +65,19 @@ struct CreditCardOrderPayload: Encodable {
     let expiryYear: String
     let ccv: String
 }
+
+struct ChangePaymentMethodPayload: Encodable {
+    let paymentMethod: String
+    let clientCpfCnpj: String?
+    let creditCard: CreditCardOrderPayload?
+    let creditCardHolderInfo: SaveCardHolderInfoPayload?
+    let savedCardId: String?
+}
+
+struct ChangePaymentMethodResult: Decodable {
+    let paymentMethod: String?
+    let paymentLocation: String?
+    let paymentId: String?
+    let paymentPayload: CreateOrderPaymentPayload?
+    let payment: CreateOrderPaymentInfo?
+}

pedi-foods/Sources/PediFoods/Services/ApiService.swift

@@ -451,6 +451,12 @@ final class ApiService {
         return try await sendEnvelope(req)
     }
 
+    func changePaymentMethod(storeId: String, orderId: String, payload: ChangePaymentMethodPayload) async throws -> ApiEnvelope<ChangePaymentMethodResult> {
+        let body = try JSONEncoder().encode(payload)
+        let req = ApiRequest(path: "/api/store/\(storeId)/orders/\(orderId)/payment-method", method: "PATCH", module: .store, requiresAuth: true, body: body)
+        return try await sendEnvelope(req)
+    }
+
     // MARK: - Profile CPF
 
     func updateProfileCpf(cpf: String) async throws -> ApiEnvelope<EmptyResult> {