webui: Add user birthday settings

- Store birth month and day in user_pref with default 10/18
- Migrate existing user_pref rows to fill missing birthday fields
- Expose birthday editing in the webui profile page
- Replace hardcoded birthday values in user info, top info, and product list responses
- Fix birthday month/day field alignment in the profile form

Signed-off-by: Sean Du <do4suki@gmail.com>

internal/handler/api/payment/payment.go

@@ -1,11 +1,15 @@
 package payment
 
-import "fmt"
+import (
+	"fmt"
 
-func PaymentApi(action string) (res any, err error) {
+	"github.com/gin-gonic/gin"
+)
+
+func PaymentApi(ctx *gin.Context, action string) (res any, err error) {
 	switch action {
 	case "productList":
-		res, err = productList()
+		res, err = productList(ctx)
 	default:
 		err = fmt.Errorf("unimplemented action: payment: %s", action)
 	}