Add Android initial audio session options

[hiroshihorie]

Summary

• Add LiveKitClient.initialize(initialAudioSessionOptions: ...) for Android WebRTC audio-device initialization.
• Seed Android automatic audio-session policy from the same initial options so playback-first apps do not need to immediately call AudioManager.setAudioSessionOptions(...) with the same preset.
• Rename the playback preset to AudioSessionOptions.mediaPlayback() for clearer intent.
• Avoid sticky Android speaker routing when updating speaker preference.
• Update audio session docs and change entry.

Runtime behavior

Android uses AudioSessionOptions in two places with different timing:

API	Timing	What changes
LiveKitClient.initialize(initialAudioSessionOptions: ...)	Before WebRTC initializes.	Passes Android audio configuration into flutter_webrtc/WebRTC ADM creation. This is where WebRTC playout AudioAttributes such as usageType and contentType are set. It also seeds LiveKit's automatic Android session policy.
AudioManager.instance.setAudioSessionOptions(...)	Runtime.	Replaces LiveKit's stored session policy, switches to manual management, and applies LiveKit's platform session behavior: Android audio mode, audio focus mode, stream type, focus ownership, routing handler policy, and iOS category/options/mode.

The important Android limitation is that WebRTC playout AudioAttributes are still initialization-time configuration. Calling AudioManager.setAudioSessionOptions(...) at runtime applies LiveKit's platform session policy, but it does not mutate the AudioAttributes on an already-created WebRTC audio device module. For playback-first Android apps that need media volume/routing from WebRTC playout, pass AudioSessionOptions.mediaPlayback() to LiveKitClient.initialize(...) before connecting.

Validation

• flutter test --no-pub test/audio/audio_session_test.dart
• `flutter analyze --no-pub

[Copilot]

Pull request overview

This PR adds Android startup-time audio session configuration so apps can set WebRTC’s initialization-time playout AudioAttributes (e.g., media vs voice) before the WebRTC audio device module is created, while also seeding LiveKit’s automatic Android session policy from the same initial intent.

Changes:

• Add LiveKitClient.initialize(initialAudioSessionOptions: ...) and plumb it into rtc.WebRTC.initialize(...) options via a new internal helper.
• Seed AudioManager’s automatic Android policy from initialization options and update Android policy resolution to use current AudioSessionOptions.
• Rename the media preset constructor to AudioSessionOptions.mediaPlayback(), update docs/tests, and adjust Android speaker routing to avoid sticky device selection.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
test/audio/audio_session_test.dart	Updates preset naming and adds coverage for seeding initial options + WebRTC init options mapping.
lib/src/support/webrtc_initialize_options.dart	New internal builder for flutter_webrtc initialize options, including Android audio configuration.
lib/src/livekit.dart	Extends LiveKitClient.initialize with initialAudioSessionOptions and seeds AudioManager on Android.
lib/src/audio/audio_session.dart	Renames the media preset constructor to mediaPlayback().
lib/src/audio/audio_session_policy.dart	Changes Android automatic policy resolution to use current options.android.
lib/src/audio/audio_manager.dart	Adds internal setInitialAudioSessionOptions to seed automatic-mode intent without switching to manual.
docs/audio.md	Documents Android timing differences and how to use initialization-time media playback intent.
android/src/main/kotlin/io/livekit/plugin/LKAudioSwitchManager.kt	Updates speaker routing to rely on preferred device list and avoid sticky selections.
.changes/android-media-routing	Changelog entries for Android initialization audio attributes, default policy seeding, and routing behavior.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.