feat(v2): 多币种 product(ProductPrice 分币价目 + v1 元回退)+ 结算币种由渠道能力驱动

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013nMthbVEmQquxBRKb9Fj8u

internal/gateway/gateway_test.go

@@ -18,11 +18,19 @@ import (
 
 type stubResolver struct{}
 
-func (stubResolver) Resolve(sku string) (int64, string, string, string, error) {
+func (stubResolver) Resolve(sku, currency string) (int64, string, string, error) {
 	if sku != "pro_year" {
-		return 0, "", "", "", gateway.ErrProductNotFound
+		return 0, "", "", gateway.ErrProductNotFound
+	}
+	// 结算币种驱动金额:USDT 6 位, 其余按分。测试只用 fake(USDT)。
+	switch currency {
+	case "USDT":
+		return 29990000, "Pro 年付", "pro_year", nil
+	case "CNY":
+		return 19900, "Pro 年付", "pro_year", nil
+	default:
+		return 0, "", "", gateway.ErrProductNotFound
 	}
-	return 29990000, "USDT", "Pro 年付", "pro_year", nil
 }
 
 type spyEnqueuer struct {
@@ -152,3 +160,15 @@ func TestRetrySwitchesAccount(t *testing.T) {
 		t.Fatalf("retry 应换到 fake-a2, got %+v", pend)
 	}
 }
+
+func TestCreateOrderCurrencyFromChannelCapability(t *testing.T) {
+	g, _, _, orders := newGateway(t) // fake provider, SettleCurrencies=["USDT"]
+	res, err := g.CreateOrder(context.Background(), gateway.CreateOrderInput{SKU: "pro_year", Method: "fake"})
+	if err != nil {
+		t.Fatalf("create: %v", err)
+	}
+	o, _ := orders.GetOrder(res.OrderNo)
+	if o.Currency != "USDT" || o.AmountMinor != 29990000 {
+		t.Fatalf("order = %s/%d want USDT/29990000", o.Currency, o.AmountMinor)
+	}
+}