Fix the two failures the fleet power-QA sweep exposed
- Gray (IP5306): test_battery_voltage_plausible asserted a LiPo voltage
range on every DUT, but the IP5306 has no battery-voltage ADC — the
backend structurally reports 0 mV. Key the assertion on the PMIC model
and assert the structural 0 for IP5306 (HIL: model=IP5306 batt_pct=100
charging=1, batt_mv=0).
- AXP backend: the boot-time PMIC probe can transiently NACK right after
a serial-open DTR/RTS reset, leaving the whole boot with no PMIC
(model=none, 0 readings) — observed intermittently on core2_v13 and
plus1. Add a bounded lazy re-probe (one retry on first telemetry read)
so a single missed probe no longer costs the boot's telemetry. Verified
on core2_v13: 3 consecutive full power-QA runs, 5/5 each.
Claude-Session: https://claude.ai/code/session_01SV58JXhfxhhc9DC6vdjBo4