Under JP_STRICT mode, add energy-based carrier sensing loop before CAD:
- Sample RSSI continuously for >= 5ms before each TX attempt
- If RSSI exceeds threshold at any point, trigger random backoff
- ARIB STD-T108 requires energy-based sensing; LoRa CAD alone is
insufficient as it only detects LoRa preambles
This satisfies the minimum 5ms continuous sensing requirement for
the 920.6-922.2 MHz zone (specified low power radio, LBT mode).
Test results (JP LoRa SF12/BW125/CR4-8, simultaneous DM):
- 16-char: 2/2 success, delivered within 1:03-1:50
- 1-char: 3/4 success, delivered within 0:46-2:11
(shorter airtime reduces RSSI detection window)
1. warm sleep
2. wake to stdby
3. Calibrate(0x7F) to reset all internal blocks
4. re-apply DIO2 RF / boosted gain & register patch to make sure
everything is as it was
This change counts when readData returns an err code other than RADIOLIB_ERR_NONE. In most cases this is going to be a CRC error. This counter is exposed in the `stats-packets` command, and in the repeater stats payload (4 additional bytes to the payload, which is now 56 bytes with this change. My incompetent robot claims the total payload size is 96 bytes (unverified but probably close).
