Replace etcp_router_bind/etcp_route_send/etcp_router_unbind with
direct etcp_bind/etcp_send/etcp_unbind + find-conn-by-node_id helpers.
Same approach as db_sync (0x20). Service IDs unchanged (0x30, 0x31).
- chat_core_connect_auto: direct ETCP connect from SQLite (no BGP)
- auto_connect: parallel connect to peers with 3s timeout, retry 10s
- RTT saved to node_addresses on disconnect
- vertical status bar + circle badge with online count per channel
- ChannelListView prevents deselection
chat_sync_push: add chain_hash parameter, use it instead of zeros
(fixes chain_hash mismatch → all PUSH messages were rejected)
on_db_sync_insert: pass computed chain_h to chat_sync_push
cs_handle_channel_join: call member_sync_start for the joiner
(server now initiates member sync when client joins.
Previously merkle_sync was only started by client → timeout
because server never responded)
cs_handle_welcome: add DEBUG_INFO before member_sync_start on client side
- 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