Add variant definition, board JSON, and TBeamBoard integration for the
LilyGo T-Beam 1W with SX1262 radio and 1W PA.
Includes:
- Board variant with pin mappings for SX1262, GPS, OLED, fan control
- AXP2101 PMU power rail configuration for T-Beam 1W
- ADC-based battery voltage fallback (2S Li-ion, 7.4V nominal)
- Temperature-based fan control for 1W PA cooling
- GPIO fallback for GPS power when PMU is not present
- Companion BLE, Repeater, Room Server, and ESPNow Bridge environments
Co-Authored-By: Oz <oz-agent@warp.dev>
