fix(spotify): transfer playback when no device is active

[slimski]

Summary

Recover context-less Play commands when Spotify has no active playback device.

When transfer_playback_on_error is enabled and a non-default output_device is configured, the Spotify app now checks for active playback before resuming. If none exists, it uses the existing transferPlayback(deviceId) path, which transfers playback to the configured device with play: true.

Normal Play behavior is preserved when playback is already active, the output is set to Default, recovery is disabled, or a track/playlist context was supplied.

Reproduction

1. Configure a Spotify Connect device as DeskThing's output.
2. Play Spotify on that device.
3. Transfer playback to another device.
4. Close Spotify on the other device so no playback device remains active.
5. Press Play on Car Thing.

Previously, DeskThing called PUT /v1/me/player/play, which returned 404 because no device was active.

Testing

• Confirmed the equivalent transfer behavior against Spotify app 0.11.1 with a Spotify Connect output.
• Ran npm run build-server successfully.