DEVLOG #19

I activated the new mmWave firmware and got the live 25-second preflight to
pass once, but the first empty-room recording did not complete.

The main work was hardening the transport: the firmware now sends redundant
radar packets, while the server handles reordering, duplicates, short CSI gaps,
and recent diagnostics instead of relying on cumulative counters. The UI also
gained a controlled empty-room countdown.

The remaining failure is intermittent: the sensor stays online and reports no
local UDP send errors, but the server still recorded packets_lost=10 and
packets_rejected=324. The empty-room capture lasted only 4.8 s for radar
and 5.1 s for CSI, so it is not a valid calibration reference.

No calibration, training, or blind position result is claimed yet.

Next: expose the exact reject reason and sequence-gap timing, fix the remaining
transport problem, and repeat the complete empty-room measurement.