- Add last_msg_at column to channels table
- Update last_msg_at on every message insert (send/receive)
- Parameterize getChannels() with ChannelSortMode enum (Alphabetical/Recent)
- Add getChannelLastMessage() for preview text in channel list
- Add sorting combo to Profile settings page (stored in ui_state)
- Reload channels on message receive when sort is recent
Add author_node_id:8 to GUI_EVT_MSG_RECEIVED data format.
Callback now includes uint64_t author parameter.
SoundManager::play('msg_incoming') only when author != myNodeId.
Evgeny