Use nonblocking AudioRecord reads with data and timestamp deadlines. Serialize idempotent close, finish interrupted joins before release, isolate callback failures, and abort stereo fallback when partial-record cleanup fails.
Close failed shared readers to new subscriptions, roll back worker startup, isolate observers, preserve interrupt state, and release the last consumer exactly once. Add an independent capture-tests JVM module to the standard Android unit-test task.
Validation: 38 capture scenarios (25 AudioRecord plus 13 PCM/PTT), 455 JVM tests, assembleDebug, core build, and full check.sh (225 tests plus proxy/burst/load) passed.
- 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
evgeny