fix(ios): stop interrupting other apps' audio on play and fix session deactivation

[WYSIATI]

Problem

Two iOS audio session issues that affect apps playing short sound effects while the user has background music (Spotify, Apple Music, etc.):

1. play() interrupts other apps' audio on every call

play() calls [[AVAudioSession sharedInstance] setActive:YES error:nil] on every invocation. Even when the app's audio category is configured with mixWithOthers, this per-play activation triggers iOS audio route reconfiguration that pauses other audio sessions.

Additionally, play() registers NSNotificationCenter observers for AVAudioSessionInterruptionNotification on every call without removing previous registrations. The audioSessionChangeObserver auto-resumes playback on InterruptionTypeEnded, causing unexpected sound replay after lock screen, phone calls, or Siri.

2. setActive(false) doesn't notify other apps to resume

setActive(false) calls [session setActive:NO error:nil] without the AVAudioSessionSetActiveOptionNotifyOthersOnDeactivation flag. Without this flag, other apps are never notified they can resume playback — their audio stays paused permanently.

Fix

1. Remove setActive:YES and observer registration from play(). Audio session lifecycle should be managed by the app via setCategory/setActive, not implicitly by the library on every play call. AVAudioPlayer.play activates the session implicitly when needed.

2. Pass notifyOthersOnDeactivation in setActive(false). When active=false, use [session setActive:NO withOptions:AVAudioSessionSetActiveOptionNotifyOthersOnDeactivation error:nil] so other apps know they can resume.

Migration

Apps that relied on the implicit setActive:YES in play() should add an explicit call during setup:

Sound.setCategory('Playback', true); // Set category with mixWithOthers
Sound.setActive(true);               // Activate session once

Apps that relied on auto-resume after interruptions should implement their own AppState listener.

Related Issues

• Playback from other source is not resumed after playing is finished #762 — Playback from other source is not resumed after playing is finished
• how to make it just like the system sound, don't interrupt the music playback #480 — How to make it just like the system sound, don't interrupt the music playback
• [iOS] setActive method doesn't resume a music #419 — setActive method doesn't resume a music
• Music stops on initial app startup  #559 — Music stops on initial app startup