Native Media Player Notification for Mobile Apps

[alan-altruy]

Description
Add native media session integration for the Home Assistant Companion App, allowing media_player entities to appear as real system media controls — similar to Spotify, YouTube Music, or other media apps.

When enabled, playback from supported media_player entities (e.g. Sonos, Chromecast, DLNA, etc.) would automatically create a native Android media notification with:

• The current track title and artist
• Album art / thumbnail (if available)
• Playback controls (play/pause, next, previous)
• Optional volume control slider
• Integration into the system’s media output switcher

This should not rely on notify.mobile_app, but instead use Android’s MediaSession API (and iOS’s equivalent if possible).

Why this matters
Currently, media control via Home Assistant is limited to:

• Dashboard cards (which require the app to be open)
• Manual notify.mobile_app messages with command_media (limited and app-specific)

A true system-level media session would:

• Offer a seamless experience across the lock screen, notification shade, and Android Auto
• Allow automations like starting/stopping media to reflect natively on the device
• Make Home Assistant feel like a first-class media controller, not just a remote app

Example scenario

1. I start playback on media_player.sonos.

2. A native media notification appears showing:

   • “Daft Punk – Get Lucky”
   • Album cover
   • Play/Pause, Next, Previous controls

3. If I swipe away the notification, an automation could trigger media_player.media_stop.

Optional enhancements

• Select which entities should create a media session (e.g. configurable in the app)
• Add automation triggers when the media session starts/stops/dismisses
• Sync media session state with the entity in real time

Platform(s)

• Android (via MediaSessionCompat / MediaStyle Notification)
• iOS (via MPNowPlayingInfoCenter if possible)