fix: 支付页去掉货币列，包年/永久货币由后端自动带

Product 映射只保留计划与 PROD_xxx；包年默认 CNY、永久默认 USD，避免误填干扰。

backend/internal/service/payment/waffo.go

@@ -453,15 +453,17 @@ func productIDForPlan(cfg WaffoConfig, planType string) string {
 }
 
 func currencyForPlan(cfg WaffoConfig, planType string) string {
-	switch strings.TrimSpace(planType) {
+	switch strings.TrimSpace(strings.ToLower(planType)) {
 	case "yearly", "monthly":
 		if cfg.CurrencyYearly != "" {
 			return cfg.CurrencyYearly
 		}
+		return "CNY" // OpsXshell 包年默认人民币 // Logan.Li
 	case "perpetual", "lifetime":
 		if cfg.CurrencyPerpetual != "" {
 			return cfg.CurrencyPerpetual
 		}
+		return "USD" // OpsXshell 永久默认美元 // Logan.Li
 	}
 	if cfg.Currency != "" {
 		return cfg.Currency