- 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
- Sound files loaded from filesystem (sound_dir in INI config, absolute or relative)
- Per-event enable/disable + volume stored in DB (ui_state table)
- SoundManager: setEvent(), effective volume = master * per-event
- SoundSettingsPage UI: 4 event rows (checkbox + slider)
- chat_core_save_ui_state() for async DB writes via uasync thread
- DbManager::getUiStateInt() for reading settings from GUI thread
- Default sounds copied to sounds/ dir next to DB, config entries written