Fix device signing/companion ID, duplicate-device crash, background updates, and add level bubble to Live Activity

- Assign the shared development team to the widget extension and watch
  complication targets, and correct the watch app's companion bundle
  identifier so on-device installs succeed after the bundle ID rename
  to de.s0.fototeddy.VanAligneiOS.
- Guard against two ConfiguredDevices sharing a peripheralID (e.g. a
  double-tapped "Sichern"), which crashed BluetoothManager's
  Dictionary(uniqueKeysWithValues:) on launch.
- Keep Bluetooth running in the background while a Live Activity is
  active, so lock screen/CarPlay keep receiving fresh readings instead
  of freezing at the last value before backgrounding.
- Render the actual bubble-level graphic (not just a static icon) in
  the Live Activity's lock screen view and expanded Dynamic Island.

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

CamperMonitor/LiveActivity/LevelActivityManager.swift

@@ -13,6 +13,11 @@ final class LevelActivityManager {
     private(set) var trackedDeviceID: UUID?
     @ObservationIgnored private var activity: Activity<LevelActivityAttributes>?
 
+    /// Ob gerade irgendeine Aktivität läuft – die App muss dafür im
+    /// Hintergrund weiter nach dem Neigungsmesser funken, sonst friert die
+    /// Anzeige beim ersten Sperren des Bildschirms ein.
+    var isActive: Bool { trackedDeviceID != nil }
+
     func isActive(for deviceID: UUID) -> Bool {
         trackedDeviceID == deviceID && activity != nil
     }