The 1.0 Python mux, mirroring the Rust donglora-mux 1.0 one-for-one and implementing the full §13 multi-client semantics on the DongLoRa Protocol v2 wire format.
* Structural rewrite. donglora_mux/{daemon,intercept,session,tagmap}.py replace the 601-line __init__.py monolith.
* Tag-aware dispatch. TagMapper with skip-zero allocation and per-client bulk drop on disconnect. Multiple clients can have commands in flight concurrently; the single-oneshot response slot is gone.
* Full §13.2 multi-client SET_CONFIG semantics. Tracks (client_id, modulation) lock owner and synthesizes OK(APPLIED/MINE), OK(ALREADY_MATCHED/OTHER), or OK(LOCKED_MISMATCH/OTHER).
* TX loopback fan-out (§13.4). On TX_DONE(TRANSMITTED) the mux synthesizes an RX frame with origin = LOCAL_LOOPBACK for every connected client except the transmitter.
* Async ERR(EFRAME) fan-out: tag-0 framing errors are broadcast to all clients.
* Per-client TX cache on ClientSession so the loopback fan-out does not need the sender to re-buffer.
* Socket and serial fcntl.flock to prevent multiple mux instances from fighting over the same dongle or socket path.
* 500 ms keepalive matching PROTOCOL.md §3.4 (2x margin on the 1 s inactivity timer), replacing the 5 s cadence from 0.x.
* Clean SIGINT / SIGTERM shutdown: per-client handler tasks are tracked and cancelled, so blocked reader.read() calls no longer pin the event loop open.
Add keepalive ping (5s interval, 2s timeout) to detect unresponsive
dongles behind UART bridges where the serial port stays open across
ESP32 resets. On reconnect, saved radio config and RX state are
re-sent so connected clients continue working transparently.
Also fix serial port opened without baud rate (defaulted to 9600
instead of 115200), preventing connection to UART boards.
swaits
