feat(nodes): per-node client IP attribution for IP-limit

Record each panel's own Xray IP observations under its panelGuid and merge each node's guid-keyed report on the master, so the panel can tell which node a client IP is connecting through (the flat inbound_client_ips union is pushed back to every node and cannot attribute). Adds the NodeClientIp model + migration, the clientIpsByGuid endpoint and node-sync merge, node-name labels in the client IP log, and cleanup on node deletion.

internal/database/migrate_data.go

@@ -50,6 +50,7 @@ func migrationModels() []any {
 		&model.ClientExternalLink{},
 		&model.InboundFallback{},
 		&model.NodeClientTraffic{},
+		&model.NodeClientIp{},
 		&model.OutboundSubscription{},
 	}
 }