feat: 新增管理员踢下线 VPN 客户端功能

- vpn/service.go: ClientInfo 增加 user_id 字段，新增 KickUser 方法
  用读锁收集目标连接后逐个关闭 WebSocket，返回断开数量
- vpn/tunnel.go: info() 填充 UserID
- handler/vpn.go: 新增 KickUserClient handler，校验用户存在后调用 KickUser
- router.go: 注册 DELETE /api/admin/vpn/clients/:id
- VpnView.vue: 在线客户端表格新增操作列与踢下线按钮，handleKick 确认后调用 API 并刷新
- zh.ts/en.ts: 新增 kick/confirmKick/kickFailed 国际化 key

internal/handler/vpn.go

@@ -406,3 +406,26 @@ func DeleteVpnReservation(c *gin.Context) {
 	}
 	c.JSON(http.StatusOK, gin.H{"message": "删除成功"})
 }
+
+func KickUserClient(c *gin.Context) {
+	idStr := c.Param("id")
+	id, err := strconv.ParseUint(idStr, 10, 64)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "参数错误"})
+		return
+	}
+
+	var user model.User
+	if err := db.DB.First(&user, id).Error; err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "用户不存在"})
+		return
+	}
+
+	if vpn.VPN == nil || !vpn.VPN.Running() {
+		c.JSON(http.StatusOK, gin.H{"message": "VPN 服务未运行", "kicked": 0})
+		return
+	}
+
+	n := vpn.VPN.KickUser(uint(id))
+	c.JSON(http.StatusOK, gin.H{"message": "已断开用户连接", "kicked": n})
+}

internal/router/router.go

@@ -46,6 +46,7 @@ func Setup(r *gin.Engine) {
 		admin.GET("/vpn/reservations", handler.ListVpnReservations)
 		admin.POST("/vpn/reservations", handler.CreateVpnReservation)
 		admin.DELETE("/vpn/reservations/:id", handler.DeleteVpnReservation)
+		admin.DELETE("/vpn/clients/:id", handler.KickUserClient)
 	}
 
 	distDir := http.Dir("./dist")

internal/vpn/service.go

@@ -374,10 +374,26 @@ func (s *VpnService) ClientList() []ClientInfo {
 }
 
 type ClientInfo struct {
+	UserID      uint   `json:"user_id"`
 	Username    string `json:"username"`
 	IP          string `json:"ip"`
 	IP6         string `json:"ip6,omitempty"`
 	ConnectedAt string `json:"connected_at"`
 }
 
+func (s *VpnService) KickUser(userID uint) int {
+	s.mu.RLock()
+	var toClose []*tunnelConn
+	for c := range s.clients {
+		if c.user.ID == userID {
+			toClose = append(toClose, c)
+		}
+	}
+	s.mu.RUnlock()
+	for _, c := range toClose {
+		c.close()
+	}
+	return len(toClose)
+}
+
 var VPN *VpnService

internal/vpn/tunnel.go

@@ -79,6 +79,7 @@ func (c *tunnelConn) close() {
 
 func (c *tunnelConn) info() ClientInfo {
 	ci := ClientInfo{
+		UserID:      c.user.ID,
 		Username:    c.user.Username,
 		IP:          c.assignedIP.String(),
 		ConnectedAt: c.connectedAt.Format("2006-01-02 15:04:05"),