[Android Auto][CAL] Official v2.0.0 sideloaded APK falls back to the legacy media UI on real vehicles

Duplicate Check

• I searched the existing Android Auto issues and did not find a report specifically covering the CAL UI and trusted-source distribution problem.

Summary

The new Android Auto Car App Library UI is present in SimpMusic v2.0.0, but it does not appear when the official APK is installed from GitHub and used in a real vehicle.

Android Auto continues to display the legacy MediaBrowser interface with tabs such as Home, Songs, Favorites, and Other.

Steps to Reproduce

1. Install the official SimpMusic v2.0.0 APK from GitHub Releases.
2. Enable Android Auto developer mode.
3. Enable Unknown sources.
4. Enable CAL Beta Features.
5. Connect the phone to a real Android Auto vehicle.
6. Open SimpMusic from the Android Auto launcher.

Actual Behavior

Android Auto displays the legacy MediaBrowser UI instead of the new Car App Library templated UI.

The application itself works and appears in Android Auto, but the new CAL service is not selected.

Expected Behavior

Android Auto should launch the new Car App Library interface implemented in PR #2235, or the documentation should clearly explain that this UI cannot be used in a real vehicle with the publicly distributed APK.

Device Information

• SimpMusic version: 2.0.0
• Version code: 57
• Package: com.maxrave.simpmusic
• Device model: SM-F966B
• Android Auto version: 17.4.663054-release
• Installation source: Official GitHub release downloaded using Samsung Internet
• Real vehicle connection
• CAL Beta Features: Enabled
• Android Auto developer mode: Enabled

ADB Evidence

The installed package is the correct v2.0.0 release:

versionCode=57
versionName=2.0.0

Start by reviewing the Car App Library implementation in PR #2235 and reproducing the behavior with the official v2.0.0 APK, Android Auto developer mode, Unknown sources, and CAL Beta Features enabled. Done means the new CAL interface launches in a real vehicle, or the documentation clearly explains the limitation for the publicly distributed APK.