Feature Request: Support separate playback speed and effects profiles for Android Auto

### Description
Currently, when using Pocket Casts on Android Auto, the playback session uses the same global or podcast-level playback speed and effects as the mobile app. Many users listen at faster speeds on their mobile devices (e.g., 1.4x - 2.0x) but prefer a standard speed (1.0x) when driving for better clarity or safety.

Because the playback settings are unified across both contexts, users must manually cycle the playback speed down when getting in the car and cycle it back up when they resume listening on their phone.

### Proposed Solution
Add an option under **Profile > Settings > Playback** to enable separate playback settings for Android Auto.
When enabled, the app should:
1. Maintain a separate user preference profile for Android Auto (speed, trim silence, volume boost).
2. Monitor Android Auto connection status (using `CarConnection.type` / `Util.isAndroidAutoConnectedFlow`).
3. Dynamically switch the active player's `PlaybackEffects` when the connection state changes (e.g., automatically dropping to the Android Auto profile speed when starting/resuming playback in the car, and restoring the mobile/podcast speed profile upon disconnection).
4. If speed/effects are changed while Android Auto is active, persist those changes to the Android Auto profile rather than the global/podcast effects.

Start with the Profile > Settings > Playback entry point and trace how PlaybackEffects are stored and applied. Read CarConnection.type and Util.isAndroidAutoConnectedFlow to understand connection changes, then define separate Android Auto preferences whose updates and restoration are complete when playback switches contexts.

Written by the indexing model from the issue text.