- Replace hardcoded provider prefix checks with resolveEffectiveMetadataProvider using replacesBuiltInProviders manifest capability
- Add preparing/downloading/finalizing progress status constants and SetItemPreparing/SetItemDownloading APIs
- Expose setDownloadStatus to extension JS runtime for fine-grained progress control
- Skip lyrics search for instrumental tracks detected by title heuristic
- Pass tidal/qobuz IDs to extension checkAvailability for richer matching
- Add shouldAbortCancelledFallback helper for robust cancellation propagation
- Add resolvePreferredTrackIDForExtension for intelligent track ID selection per extension
- Remove ambiguous Auto/Default search provider option, always resolve to concrete provider
- Add tests for shouldAbortCancelledFallback and progress status transitions