The CALIBRATE_ALL (0x7F) command inside resetAGC() clears bit 0 of the
undocumented 0x8B5 register. That bit is set once in init() by #9571 and
#9777 to improve SX1262 RX sensitivity, and the AGC-reset path was not
re-applying it. Result: every SX1262 node silently loses the RX
sensitivity patch ~60s after boot and never recovers until reboot.
Empirically confirmed on Heltec Mesh Node T114 (nRF52840 + SX1262):
- Post-calibration read of 0x8B5 = 0x04 (bit 0 cleared)
- After re-apply: 0x05 (bit 0 set)
Reproducible every AGC_RESET_INTERVAL_MS tick.
Fix re-applies the register bit alongside the existing post-calibration
re-applies (setDio2AsRfSwitch, setRxBoostedGainMode).
