ios: reorderable tab bar with more tabs, debug log export, AirPlay picker, more room above seeker

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

ios/Stemify/Playback/PlaybackManager.swift

@@ -181,6 +181,7 @@ final class PlaybackManager: StemEngineListener, @unchecked Sendable {
 
     /// Surfaces a message wherever messages show (toasts on the phone, an alert in the car).
     func report(_ text: String) {
+        Log.shared.error("report", text)
         message = AppMessage(text: text)
         messageListeners.values.forEach { $0(text) }
     }
@@ -797,6 +798,7 @@ final class PlaybackManager: StemEngineListener, @unchecked Sendable {
             guard let self, let info = n.userInfo,
                   let raw = info[AVAudioSessionInterruptionTypeKey] as? UInt,
                   let type = AVAudioSession.InterruptionType(rawValue: raw) else { return }
+            Log.shared.info("session", "interruption \(type == .began ? "began" : "ended")")
             switch type {
             case .began:
                 // A stale "began" arrives after the app was suspended; the session wasn't really taken.
@@ -813,12 +815,14 @@ final class PlaybackManager: StemEngineListener, @unchecked Sendable {
         nc.addObserver(forName: AVAudioSession.routeChangeNotification, object: nil, queue: .main) { [weak self] n in
             guard let self, let raw = n.userInfo?[AVAudioSessionRouteChangeReasonKey] as? UInt,
                   let reason = AVAudioSession.RouteChangeReason(rawValue: raw) else { return }
+            Log.shared.info("route", "change reason=\(reason.rawValue) now \(AirRoute.describe())")
             // Headphones unplugged or Bluetooth gone: don't carry on out of the speaker.
             if reason == .oldDeviceUnavailable && self.playWhenReady { self.pause() }
             self.eq.refreshRoute()
         }
         nc.addObserver(forName: AVAudioSession.mediaServicesWereResetNotification, object: nil, queue: .main) { [weak self] _ in
             guard let self else { return }
+            Log.shared.error("session", "media services reset")
             let was = self.playWhenReady
             let pos = self.positionMs()
             self.currentToken = -1