Add HTTP/serial file transfer, broadcast beacon, SD telemetry
- HTTP server on port 8080: GET /sdcard/<path> for SD file download
- Serial: sdcard send <file> streams hex-encoded; tools/sdcard_recv.py receives
- Broadcast beacon (UDP 5555): advertise IP, MAC, fiwi-telemetry for discovery
- tools/beacon_listen.py: listen and optionally download fiwi-telemetry per device
- SD commands: list, send, delete; status shows fiwi-telemetry and telemetry-status
- Monitor start: MCS telemetry -> fiwi-telemetry on SD by default (every 10s)
- telemetry-status on SD: persist download stats across reboots
- Kconfig: BEACON_INTERVAL_SEC, TELEMETRY_AUTO_DELETE_AFTER_DOWNLOAD
Co-authored-by: Cursor <cursoragent@cursor.com>
1eb04acd25