Fix memory leaks in AppStateListener and Room

[viachaslauinnowise]

Fix: memory leaks in AppStateListener observers and Room cleanup

AppStateListener:

• Store NotificationCenter observer tokens for proper cleanup
• Add deinit to remove all observers
• Use [weak self] in all observer closures

Room:

• Remove from AppStateListener.delegates in deinit (safety net)
• Explicitly remove in cleanUp() (primary path)
• Prevent memory leaks when Room is destroyed without cleanUp()

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