Enable SolarXiao Room Server power profiles and late-detection history

docs/solarxiao_power.md

@@ -1,7 +1,8 @@
 # SolarXiao carrier profiles, MPPT and battery controls
 
-SolarXiao Repeater firmware supports the CN3791 Base, older BQ24650 Advanced and
-LTC4162/INA260 MPPT carriers in Full and Reduced builds. Use USB CLI or the
+SolarXiao Repeater and QSPI OTA Room Server firmware support the CN3791 Base,
+older BQ24650 Advanced and LTC4162/INA260 MPPT carriers in Full and Reduced builds.
+Use USB CLI or the
 authenticated administrator CLI over LoRa. Ship mode and
 saved-policy reset require local USB. Commands do not change RF settings.
 
@@ -82,7 +83,7 @@ resistors, switches and a solder jumper. An OTA update cannot measure those
 signals or change those setpoints without additional hardware connections.
 
 Manual Basic mode suppresses native LTC4162/INA260 polling, register reads/writes,
-replay and telemetry/history channels 2..13. `get mppt`, `set mppt ...` and
+replay and native measurements on channels 2..13. `get mppt`, `set mppt ...` and
 `mppt ...` explain that Basic Base/Advanced layouts have no digital charger interface.
 Pending auto mode only probes INA260 identity; it does not access the charger.
 The generic sensor scanner still reserves native addresses 0x40 and 0x68, so it
@@ -90,6 +91,14 @@ cannot bypass that policy. Optional external sensor channels still start at 14.
 Historical samples retained from a previous carrier selection describe the old
 samples, not current sensor availability.
 
+Voltage history reserves native channel IDs 2..5 at boot, even while Auto is
+pending or Basic is selected. This is schema allocation, not chip access or a
+measurement. It lets later detection, charger input power or a manual mode
+change supply valid samples without restarting or clearing unrelated history.
+Inactive readings remain missing, and empty channels do not appear in populated
+history results. Native and optional I2C voltage history use the existing
+`get telemetry.volt.i2c <channel> [1-4]` reader: four days of 30-minute RAM samples.
+
 Where telemetry history is included, `get solar history` points to the existing
 `get telemetry.volt [1-7]` and `get telemetry.temp [1-7]` commands: 30-minute
 samples, seven days in RAM. History starts filling after boot and resets at
@@ -110,9 +119,20 @@ carrier does not erase those overrides, change RF/PA settings, modify battery
 protection, or write charger defaults. The INA260 identity verifies the monitor;
 LTC4162 chemistry and cell-count checks still independently guard charger writes.
 
-Radio target selection remains separate. Choose the existing
-`solarxiao_30S_repeater` or `solarxiao_33S_repeater` firmware target to match the
-fitted E22 radio module. The
+Radio target and role selection remain separate from the power profile:
+
+| Fitted module | Repeater | Room Server |
+| --- | --- | --- |
+| E22 M30S | `solarxiao_30S_repeater` | `solarxiao_30S_room_server_lora_ota` |
+| E22 M33S | `solarxiao_33S_repeater` | `solarxiao_33S_room_server_lora_ota` |
+
+All three power profiles work in these role builds. Room uses its existing
+onboard-QSPI OTA target, identity and application layout, with the matching
+board/storage-aware OTAFIX bootloader. The older plain `*_room_server` targets
+remain separate compatibility/recovery recipes; this native interface is
+qualified on the QSPI OTA Room targets. No legacy identity is remapped.
+
+The
 published Base Standard schematic specifies M30S; the pictured 2W Advanced
 uses M33S. Charger detection cannot identify the PA variant or select its TX
 power limits.