feat: balancer dashboard metrics + fix WebSocket Hijacker

internal/models/types.go

@@ -209,10 +209,29 @@ type ZabbixResponse struct {
 	Data []ZabbixNode `json:"data"`
 }
 
+// --- Balancer ---
+
+// BalancerInfo — состояние балансировщика для дашборда.
+type BalancerInfo struct {
+	EslConnected   bool   `json:"esl_connected"`
+	EslUptimeSec   int64  `json:"esl_uptime_sec,omitempty"`
+	EslReconnects  int64  `json:"esl_reconnects,omitempty"`
+	NatsConnected  bool   `json:"nats_connected"`
+	GatewaysTotal  int    `json:"gateways_total"`
+	GatewaysUp     int    `json:"gateways_up"`
+	GatewaysDown   int    `json:"gateways_down"`
+	FsActiveCalls  int    `json:"fs_active_calls"`
+	FsMaxSessions  int    `json:"fs_max_sessions"`
+	FsUptime       string `json:"fs_uptime"`
+	RouteTotal     int64  `json:"route_total"`
+	RouteFallbacks int64  `json:"route_fallbacks"`
+	UptimeSec      int64  `json:"uptime_sec"`
+}
+
 // --- WebSocket ---
 
 // WsMetricsMessage — сообщение, отправляемое по WebSocket.
 type WsMetricsMessage struct {
-	Type    string      `json:"type"` // "nodes_update", "node_toggle", etc
+	Type    string      `json:"type"` // "nodes_update", "balancer_update", "gateway_update", etc
 	Payload interface{} `json:"payload"`
 }