Enable SolarXiao Room Server power profiles and late-detection history

src/helpers/sensors/SolarXiaoPower.cpp

@@ -146,7 +146,8 @@ void addTelemetry(CayenneLPP& lpp) {
   for (unsigned i=0;i<3;++i) lpp.addGenericSensor(11+i,s.alerts[i]);
 }
 uint8_t voltageChannels(uint8_t* channels,uint8_t capacity) {
-  if (!selection.nativeAllowed()) return 0;
+  // History allocates its schema once at boot, before Auto can verify MPPT.
+  // Reserve stable IDs without I/O; inactive/unavailable samples stay missing.
   const uint8_t count=capacity<4 ? capacity : 4;
   for (uint8_t i=0;channels && i<count;++i) channels[i]=2+i;
   return count;

src/helpers/sensors/SolarXiaoPower.h

@@ -12,6 +12,8 @@ void service();
 bool handleCommand(const char* command, char* reply, size_t capacity, bool local);
 void addTelemetry(CayenneLPP& telemetry);
 uint8_t voltageChannels(uint8_t* channels, uint8_t capacity);
+// The channel list reserves history schema without I/O; only queryVoltages
+// returns measured samples, and remains gated by the active power profile.
 uint8_t queryVoltages(SensorManager::VoltageSensorReading* readings, uint8_t capacity);
 }}
 #endif