uasync: replace raw socket_node* handle with packed index — fixes UAF after socket_array realloc
tcp_io: defer u_free in tcp_conn_destroy via uasync_call_soon — prevents callback-chain UAF
tcp_io: guard read_cb/write_cb with NULL queue checks after deferred destroy
tcp_io: save read_queue to local before queue_data_put + NULL guard after
route_connectivity: linked-list probe_ctx — cancel all parallel probes before nq free
etcp_router: routable service packets with dst/src node_id
- etcp_router_bind/unbind: per-instance service handler registry
- etcp_route_send: send to node by id via BGP routing
- multi-hop forwarding through intermediate nodes
- loopback optimization (dst==self dispatches directly)
remote_proxy: exit node creating OS sockets on demand
- handles CONNECT/DATA/CLOSE via etcp_router
- non-blocking socket connect with uasync callbacks
- echo back response data to requesting node
tcp_proxy: etcp_transport for remote proxy
- via_node_id in mapping selects between sock/etcp transport
- unified handler for both tcp_proxy and remote_proxy roles
- config: forward = port -> ip:port via NODE_HEX [remote_proxy] section
tests: test_etcp_router (20 pkts bidirectional), test_remote_proxy (echo)