Add solar charge controller integration and firmware

App:
- New DeviceRole.solar with its own BLE session/protocol/state
  (SolarSession, VanAlignSolarProtocol, SolarState), mirroring the
  leveling sensor but deliberately not wired into the Live Activity.
- BluetoothManager now keeps an in-memory history per metric (voltage,
  current, power) instead of a single primary-metric series; cleared on
  app restart by design, not persisted to disk.
- DeviceDetailView shows a channel picker above the history chart when a
  device has more than one chartable metric.
- AddDeviceView recognizes the solar service UUID during setup.
- DemoData gets a simulated solar device so the integration can be
  checked in the simulator without hardware.

Firmware:
- Add esp32_ble_solar.yaml (Votronic solar charge controller over BLE)
  and simulated variants (esp32_ble_sim.yaml, esp32_ble_solar_sim.yaml)
  for testing without a vehicle.
- esp32_ble.yaml: set flash_size/psram for the ESP32-S3 N16R8 module.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

CamperMonitor/Views/AddDeviceView.swift

@@ -195,6 +195,8 @@ private struct ConfigureDeviceView: View {
             }
         } else*/ if discovery.isLevelSensor {
             role = .leveling
+        } else if discovery.isSolarSensor {
+            role = .solar
         } /*else if let name = discovery.name?.lowercased(),
                   ["alpicool", "icecube", "ice cube", "fridge", "cool"].contains(where: name.contains) {
             role = .fridge
@@ -206,6 +208,8 @@ private struct ConfigureDeviceView: View {
         // ohnehin darüber unter "Gefunden als".
         if discovery.isLevelSensor {
             name = "Nivellierung"
+        } else if discovery.isSolarSensor {
+            name = "Solarladeregler"
         } else if let advertised = discovery.name, advertised.count <= 20,
            advertised.contains(" ") || advertised.rangeOfCharacter(from: .decimalDigits) == nil {
             name = advertised