When the Android native TTS engine is paused or stopped but not shut down,
it holds resources and drains battery. This adds a 30-minute idle timer that
automatically shuts down the TextToSpeech engine and MediaPlaybackService
after inactivity. The engine transparently re-initializes on next use.
Also adds missing androidx.lifecycle:lifecycle-process dependency to fix
ProcessLifecycleOwner build error.
Closes#3713
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Huang Xin