Radio commands were serialized per method call, so a composite command held the lock for everything it awaited. A DM's send_msg_with_retry kept every other command waiting through all of its ACK timeouts (up to ~36 s with three attempts), stalling channel replies, other DMs, scheduled sends, and automatic message fetching. req_regions_sync did the same for each neighbor scope reply.
Serialize at the frame instead: wrap CommandHandler.send() on the handler instance, which is where every meshcore command writes its frame and waits for the radio's immediate reply. There is still at most one in-flight companion frame, paced as before, and library methods that call self.send are covered without a proxy. Waits for ACKs and remote responses now run outside the lock.
Add MeshCoreBot.radio_session() for short sequences that must not interleave, and use it for region-scoped channel sends so set scope, send, and restore stay together. The per-call lock never guaranteed that: a DM retry loop queued between set_flood_scope and send_chan_msg sent its flood attempts under the channel's scope.
- Introduced a new class `_SerializedCommands` to serialize host-to-radio commands, ensuring only one command is in-flight at a time to prevent USB-CDC buffer overruns and parser desynchronization.
- Added configuration options for `command_min_interval_ms` and `channel_fetch_interval_ms` to control pacing between commands and channel scans, improving firmware stability during reconnect sequences.
- Updated `ChannelManager` to utilize the new fetch interval during channel scans, and modified the reconnect delay to 10 seconds for gentler recovery from connection issues.
- Enhanced documentation in `config.ini.example` to reflect new settings and their purposes.
Adam Gessaman