Refresh both AGENTS guides and clarify module purpose, usage, ownership, threading, return values and wire formats in headers. Remove the unused timeout_heap freed_count field and unimplemented getter.
- u_async.c: process immediate_queue BEFORE epoll_wait in uasync_poll
- stcp_link.c: defensive NULL etcp_conn/etcp_link in stcp_link_close
- utun_instance.c: move stcp_server_list_destroy_all to Phase J (before ETCP),
add deferred drain in both Phase J and L
- stcp.h/c: STCP_HS_ENC_CLIENT 6→38, STCP_HS_ENC_SERVER 7→39,
exchange ed25519_pubkey in both handshake directions
- etcp_connections.c: copy peer_ed25519 from STCP to ETCP_CONN in
etcp_link_enter_ready_tcp; guard link->etcp in tcp_link_close_cb
- chat_sync.c: fix lk->conn NULL dereference for TCP links
- test_stcp.c: update stcp_server_create/stcp_client_connect callsites
- tools/chat_tcp_test: change transport udp→tcp
- Замена контекстного меню 'Пригласить' на кнопку + (18x18) справа снизу каждого канала с hover-эффектом
- InviteDialog: авто-копирование ссылки в буфер (Clipboard + Selection) при открытии
- JoinDialog: параметр autoJoinLink — если в буфере валидная utun:// ссылка, диалог сразу стартует подключение
- debug_ui.h: remove NDEBUG guard so GUI_ERROR works in Release builds
- invite_link.h/cpp: add error field to InviteData with specific failure reason
- joindialog: show exact decode error in QLabel instead of generic message
- chat_sync: implement invite connect flow (CHANNEL_INFO_REQ/RESP, JOIN, WELCOME)
- topo_node_sqlite: node/address table init and lookup
- utun_node: getInviteAddresses fallback from ETCP sockets
- minor fixes in mainwindow, chat_core, gui_bridge
evgeny