feat: web console with real management operations

Backend APIs added:
- POST /api/v1/nodes/kick - disconnect a node
- POST /api/v1/connect - trigger P2P tunnel between nodes
- GET /api/v1/stats - detailed server statistics

Frontend features:
- Dashboard: real stats from /api/v1/stats (cone/symm/relay counts)
- Node management: table view, kick node, configure tunnels
- SDWAN: enable/disable, CIDR config, IP allocation, online status
- P2P Connect: create tunnel between two nodes from UI
- Event log: tracks all operations

pkg/protocol/protocol.go

@@ -65,6 +65,7 @@ const (
 	SubPushSDWANConfig               // push sdwan config to client
 	SubPushSDWANPeer                 // push sdwan peer online/update
 	SubPushSDWANDel                  // push sdwan peer offline/delete
+	SubPushConfig                    // generic remote config push
 )
 
 // Sub types: MsgTunnel