feat: 批量设置用户最大连接数

前端:
- 用户列表添加 checkbox 多选（表格和网格视图）
- 选中用户后显示「批量设置连接数」按钮
- 批量设置对话框，输入连接数后批量应用

后端:
- 新增 BatchUpdateUserMaxConn repo 方法
- 新增 /api/v1/user/batch-set-max-conn API
- 返回成功/失败计数
- 加入 admin-only 路由白名单

go-backend/internal/http/handler/handler.go

@@ -138,6 +138,7 @@ func (h *Handler) Register(mux *http.ServeMux) {
 	mux.HandleFunc("/api/v1/user/update", h.userUpdate)
 	mux.HandleFunc("/api/v1/user/delete", h.userDelete)
 	mux.HandleFunc("/api/v1/user/reset", h.userResetFlow)
+	mux.HandleFunc("/api/v1/user/batch-set-max-conn", h.userBatchSetMaxConn)
 	mux.HandleFunc("/api/v1/user/quota/reset", h.userQuotaReset)
 	mux.HandleFunc("/api/v1/user/groups", h.userGroups)
 	mux.HandleFunc("/api/v1/config/get", h.getConfigByName)

go-backend/internal/http/handler/mutations.go

@@ -214,6 +214,26 @@ func (h *Handler) userUpdate(w http.ResponseWriter, r *http.Request) {
 	response.WriteJSON(w, response.OKEmpty())
 }
 
+func (h *Handler) userBatchSetMaxConn(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		response.WriteJSON(w, response.ErrDefault("请求失败"))
+		return
+	}
+	var req struct {
+		UserIDs []int64 `json:"userIds"`
+		MaxConn int     `json:"maxConn"`
+	}
+	if err := decodeJSON(r.Body, &req); err != nil || len(req.UserIDs) == 0 {
+		response.WriteJSON(w, response.ErrDefault("请求参数错误"))
+		return
+	}
+	s, f := h.repo.BatchUpdateUserMaxConn(req.UserIDs, req.MaxConn)
+	response.WriteJSON(w, response.OK(map[string]interface{}{
+		"success": s,
+		"failed":  f,
+	}))
+}
+
 func (h *Handler) userGroups(w http.ResponseWriter, r *http.Request) {
 	if r.Method != http.MethodPost {
 		response.WriteJSON(w, response.ErrDefault("请求失败"))

go-backend/internal/http/middleware/auth.go

@@ -137,7 +137,7 @@ func requiresAdmin(path string) bool {
 	}
 
 	switch path {
-	case "/api/v1/user/create", "/api/v1/user/list", "/api/v1/user/update", "/api/v1/user/delete", "/api/v1/user/reset":
+	case "/api/v1/user/create", "/api/v1/user/list", "/api/v1/user/update", "/api/v1/user/delete", "/api/v1/user/reset", "/api/v1/user/batch-set-max-conn":
 		return true
 	case "/api/v1/config/update", "/api/v1/config/update-single":
 		return true

go-backend/internal/store/repo/repository_mutations.go

@@ -1320,6 +1320,23 @@ func (r *Repository) BatchUpdateForwardStatus(ids []int64, status int) (int, int
 	return s, f
 }
 
+func (r *Repository) BatchUpdateUserMaxConn(ids []int64, maxConn int) (int, int) {
+	if r == nil || r.db == nil {
+		return 0, len(ids)
+	}
+	s := 0
+	f := 0
+	now := time.Now().UnixMilli()
+	for _, id := range ids {
+		if err := r.db.Model(&model.User{}).Where("id = ?", id).Updates(map[string]interface{}{"max_conn": maxConn, "updated_time": now}).Error; err != nil {
+			f++
+		} else {
+			s++
+		}
+	}
+	return s, f
+}
+
 func (r *Repository) CreateTunnelTx(tx *gorm.DB, name string, trafficRatio float64, typeVal int, flow int64, now int64, status int, inIP interface{}, inx int, ipPreference string) (int64, error) {
 	inIPVal := nullStringFromInterface(inIP)
 	tunnel := model.Tunnel{