feat: 用户个人页面展示当前 VPN 连接信息

- handler/vpn.go: 新增 GetMyVpnConnections，返回当前用户的在线
  VPN 连接列表（IP/连接时间）及 max_conns_per_user 上限
- router.go: 注册 GET /api/me/vpn/connections（普通用户可访问）
- ProfileView.vue: 新增"我的 VPN 连接"区块，含 n/max 徽章、
  IPv4/IPv6/连接时间表格，底部提示异常连接请修改密码
- zh.ts/en.ts: 新增 myVpnConnections/noConnections/
  abnormalConnectionHint 国际化

internal/handler/vpn.go

@@ -208,6 +208,42 @@ func UpdateVpnSettings(c *gin.Context) {
 	c.JSON(http.StatusOK, gin.H{"message": "设置已更新"})
 }
 
+type myVpnConnection struct {
+	IP          string `json:"ip"`
+	IP6         string `json:"ip6,omitempty"`
+	ConnectedAt string `json:"connected_at"`
+}
+
+func GetMyVpnConnections(c *gin.Context) {
+	userID, _ := c.Get("user_id")
+
+	maxConns := 30
+	if vpn.VPN != nil {
+		s := vpn.VPN.Settings()
+		if s.MaxConnsPerUser > 0 {
+			maxConns = s.MaxConnsPerUser
+		}
+	}
+
+	connections := make([]myVpnConnection, 0)
+	if vpn.VPN != nil && vpn.VPN.Running() {
+		for _, ci := range vpn.VPN.ClientList() {
+			if ci.UserID == userID.(uint) {
+				connections = append(connections, myVpnConnection{
+					IP:          ci.IP,
+					IP6:         ci.IP6,
+					ConnectedAt: ci.ConnectedAt,
+				})
+			}
+		}
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"max_conns_per_user": maxConns,
+		"connections":        connections,
+	})
+}
+
 type vpnStatusResponse struct {
 	Enabled   bool             `json:"enabled"`
 	Online    int              `json:"online"`

internal/router/router.go

@@ -26,6 +26,7 @@ func Setup(r *gin.Engine) {
 		auth.PUT("/me/password", handler.ChangePassword)
 		auth.GET("/me/sessions", handler.ListMySessions)
 		auth.DELETE("/me/sessions/:sessionId", handler.RevokeMySession)
+		auth.GET("/me/vpn/connections", handler.GetMyVpnConnections)
 	}
 
 	admin := r.Group("/api/admin")