✨ feat(topup): Admin-wide topup listing and route reorganization

Allow administrators to view all platform topup orders and streamline admin-only routes.

Frontend
- TopupHistoryModal: dynamically switch endpoint by role
  - Admin → GET /api/user/topup (all orders)
  - Non-admin → GET /api/user/topup/self (own orders)
- Use shared utils `isAdmin()`; keep logic centralized and DRY
- Minor UI: set admin action button theme to outline for clarity

Backend
- model/topup.go: add GetAllTopUps(pageInfo) with pagination (ordered by id desc)
- controller/topup.go: add GetAllTopUps handler returning PageInfo response
- router/api-router.go:
  - Add admin route GET /api/user/topup (AdminAuth)
  - Move POST /api/user/topup/complete to adminRoute (keeps path stable, consolidates admin endpoints)

Security/Behavior
- Admin-only endpoints now reside under the admin route group with AdminAuth
- No behavior change for regular users; no schema changes

Affected files
- model/topup.go
- controller/topup.go
- router/api-router.go
- web/src/components/topup/modals/TopupHistoryModal.jsx

model/topup.go

@@ -136,6 +136,35 @@ func GetUserTopUps(userId int, pageInfo *common.PageInfo) (topups []*TopUp, tota
 	return topups, total, nil
 }
 
+// GetAllTopUps 获取全平台的充值记录（管理员使用）
+func GetAllTopUps(pageInfo *common.PageInfo) (topups []*TopUp, total int64, err error) {
+	tx := DB.Begin()
+	if tx.Error != nil {
+		return nil, 0, tx.Error
+	}
+	defer func() {
+		if r := recover(); r != nil {
+			tx.Rollback()
+		}
+	}()
+
+	if err = tx.Model(&TopUp{}).Count(&total).Error; err != nil {
+		tx.Rollback()
+		return nil, 0, err
+	}
+
+	if err = tx.Order("id desc").Limit(pageInfo.GetPageSize()).Offset(pageInfo.GetStartIdx()).Find(&topups).Error; err != nil {
+		tx.Rollback()
+		return nil, 0, err
+	}
+
+	if err = tx.Commit().Error; err != nil {
+		return nil, 0, err
+	}
+
+	return topups, total, nil
+}
+
 // ManualCompleteTopUp 管理员手动完成订单并给用户充值
 func ManualCompleteTopUp(tradeNo string) error {
 	if tradeNo == "" {