feat(server/pay): 订单列表端点 + 分币种展示价 + 富字段详情

- GET /v1/pay/orders 订单列表(Store.ListByUser,本地台账倒序)
- catalog 增 PriceUsdtMicro(USDT 一口价展示) + SettlementCurrency/DisplayAmountMinor
- 下单按支付方式落展示金额/结算币种(crypto→USDT / 法币→CNY),webhook 覆盖实际
- GetOrder 详情回带 sku/plan/method/amount/currency/created_at/paid_at
- 新增 List 越权/倒序/富字段 + 分币种展示金额 + 详情富字段测试
- 修 3 个 pre-existing 迁移测试(renumber 后 21→23 遗留)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013nMthbVEmQquxBRKb9Fj8u

server/internal/pay/catalog.go

@@ -3,21 +3,25 @@ package pay
 import "github.com/wangjia/pangolin/server/internal/codes"
 
 // CatalogItem 是可购档位。SKU 与 pay 侧 products.biz_code 一一对应
-// (webhook product_biz_code 原样回带);PriceMinor 仅展示(CNY 分),
-// 实际扣款以 pay 侧 ProductPrice/price 为准——一致性列入联调 checklist。
+// (webhook product_biz_code 原样回带);价格字段**仅展示**(实际扣款以 pay 侧
+// per-currency ProductPrice 为准——一致性列入联调 checklist):
+//   - PriceMinor:CNY 分(支付宝/哪吒等法币渠道)
+//   - PriceUsdtMicro:USDT 微元(6 位精度,加密货币渠道)
 type CatalogItem struct {
-	SKU        string `json:"sku"`
-	Plan       string `json:"plan"`
-	Days       int    `json:"days"`
-	PriceMinor int64  `json:"price_minor"`
-	Currency   string `json:"currency"`
+	SKU            string `json:"sku"`
+	Plan           string `json:"plan"`
+	Days           int    `json:"days"`
+	PriceMinor     int64  `json:"price_minor"`      // CNY 分(展示)
+	Currency       string `json:"currency"`         // CNY
+	PriceUsdtMicro int64  `json:"price_usdt_micro"` // USDT 微元(展示;各币种一口价、非汇率换算)
 }
 
 // Catalog 三档单源。时长取宽松口径(31/92/366 覆盖大月与最长季)。
+// USDT 展示价与 pay 侧 products 一口价对齐($4.99/$12.99/$34.99),不做实时汇率换算。
 var Catalog = []CatalogItem{
-	{SKU: "pro_month", Plan: string(codes.PlanPro), Days: 31, PriceMinor: 2999, Currency: "CNY"},
-	{SKU: "pro_quarter", Plan: string(codes.PlanPro), Days: 92, PriceMinor: 6888, Currency: "CNY"},
-	{SKU: "pro_year", Plan: string(codes.PlanPro), Days: 366, PriceMinor: 19999, Currency: "CNY"},
+	{SKU: "pro_month", Plan: string(codes.PlanPro), Days: 31, PriceMinor: 2999, Currency: "CNY", PriceUsdtMicro: 4990000},
+	{SKU: "pro_quarter", Plan: string(codes.PlanPro), Days: 92, PriceMinor: 6888, Currency: "CNY", PriceUsdtMicro: 12990000},
+	{SKU: "pro_year", Plan: string(codes.PlanPro), Days: 366, PriceMinor: 19999, Currency: "CNY", PriceUsdtMicro: 34990000},
 }
 
 func CatalogBySKU(sku string) (CatalogItem, bool) {
@@ -28,3 +32,21 @@ func CatalogBySKU(sku string) (CatalogItem, bool) {
 	}
 	return CatalogItem{}, false
 }
+
+// SettlementCurrency 按支付方式给出结算币种(展示/落台账用;实际以 pay 侧为准)。
+// crypto→USDT;其余法币渠道(alipay/nezha/…)→CNY。
+func SettlementCurrency(method string) string {
+	if method == "crypto" {
+		return "USDT"
+	}
+	return "CNY"
+}
+
+// DisplayAmountMinor 按支付方式给出该档「展示金额」(下单时预估、落台账,
+// webhook 到账后由实际结算金额覆盖)。crypto→USDT 微元;法币→CNY 分。
+func DisplayAmountMinor(it CatalogItem, method string) int64 {
+	if method == "crypto" {
+		return it.PriceUsdtMicro
+	}
+	return it.PriceMinor
+}