Remove obsolete phase completion summaries and demo test scripts - Deleted `PHASE1_COMPLETION_SUMMARY.md`, `PHASE2_COMPLETION_SUMMARY.md`, `PHASE3_COMPLETION_SUMMARY.md`, and associated demo test scripts to streamline the codebase and eliminate unused documentation. This cleanup supports ongoing refactoring efforts and enhances overall project maintainability.
Enhance UnifiedTrackMetadata and Services Module - Added recommendation-specific fields and audio features to UnifiedTrackMetadata for improved track metadata handling. Updated services module to include enhanced API and recommendation services, streamlining workflows and maintaining backward compatibility.
