- 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
- block_availability: status column (0=processing, 1=completed)
- md_ba_complete_block(): DELETE old + check exists + INSERT new id
- BLOCK_PROCESSING subcmd (0x10) — INSERT with new id, no REPLACE/IGNORE
- BLOCK_RELAY_FULL subcmd (0x11) — redirect when source/relay at capacity
- relay_block_ctx: downstream forwarding from chunk file
- md_file_load: per-file source download limit (max_downloads_per_file)
- RELAY_FULL from source node when at capacity
- relay_full handler: retry existing peers, not just new ones
- sync.md: full documentation
evgeny