Prevent intermittent crash when closing OvEditor

[Gopmyc]

Description

Fixes an intermittent crash when closing OvEditor by making AudioEngine properly unsubscribe from static audio entity events during shutdown.

Root cause:

• AudioEngine subscribed to static AudioSource / AudioListener events but never removed those listeners.
• During teardown, stale callbacks could target a destroyed AudioEngine, causing undefined behavior/crash.

What changed:

• Stored listener IDs for:
  • AudioSource::CreatedEvent
  • AudioSource::DestroyedEvent
  • AudioListener::CreatedEvent
  • AudioListener::DestroyedEvent
• Explicitly removed those listeners in AudioEngine destructor before backend deinit.

Scope:

• Minimal and local changes only in OvAudio/Core/AudioEngine.*.
• No API change, no behavior change outside shutdown safety.

Related Issue(s)

Fixes #731

Review Guidance

Please review destruction/lifecycle order in AudioEngine:

• Event subscriptions are now tracked by ID.
• Event unsubscriptions happen in ~AudioEngine() before m_backend->deinit().

Files changed:

• Sources/OvAudio/include/OvAudio/Core/AudioEngine.h
• Sources/OvAudio/src/OvAudio/Core/AudioEngine.cpp

Screenshots/GIFs

N/A (no UI change)

Checklist

• My code follows the project's code style guidelines
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation accordingly
• My changes don't generate new warnings or errors