Switch the fast-GPS beacon to the firmware's canonical 16-byte wire format
(magic, key6, lat/lon microdegrees, speed km/h) — no on-wire timestamp; the
receiver stamps its own RX time. Drops compatibility with the older 19-byte app
format.
Mirror the firmware's adaptive send cadence in the app-fallback path
(LocationTrackingService): anchor + dwell motion hysteresis, EMA ground speed,
9-min stationary keepalive, fix-quality (accuracy) gate, and a post-RX hold-off
to avoid channel collisions. Parked nodes now beacon the stable anchor instead
of GPS wander.
Add the fast_gps_region config: region-scope picker in settings backed by the
firmware's fast_gps_region / fast_gps_regions custom vars.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Move BLE communication layer (command queue, frame parser/builder,
protocol constants, data models) into a standalone reusable Dart package
at ../meshcore_client. App model files become thin re-export wrappers,
keeping all existing consumers working without import changes.
