- 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
5 new tests in test_media_delivery_download:
- conn_cb starts only first block (backpressure)
- conn_cb with multiple peers
- BLOCK_DONE triggers next block relay from same peer
- assembly after all blocks validated
- peer with more blocks than dl (OOB fix verification)
md_dl_conn_cb made non-static for test visibility
md_dl_send added NULL guard for test instances without routing
media_download.h: added conn_cb extern declaration
evgeny
Evgeny