- Add PlayerStatus enum with loading/buffering/playing/error states
- Track loading elapsed time with countdown timer
- Detect buffering via timeControlStatus
- Handle playback errors with error message + retry button
- Show timeout warning after 15s of loading
- Buffering indicator in top-right corner (non-blocking)
- Localization strings for all status messages
- Remove Combine import and cancellables
- Use NSKeyValueObservation for timeControlStatus (controlled teardown)
- Invalidate itemStatusObserver before replacing playerItem
- Store endObserver token for proper removal
- Add cleanup() method called on view disappear
- Proper deinit with direct property cleanup (nonisolated-safe)
