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.

Implement Phase 3 enhancements for candidate pool persistence in recommendation agents - Introduced `SessionManagerService` to support candidate pool generation and retrieval across `UnifiedCandidateGenerator`, `DiscoveryAgent`, `JudgeAgent`, and `GenreMoodAgent`. Updated agent initialization to accept session manager, enabling efficient follow-up query handling and improved user experience. Added methods for generating and persisting large candidate pools, as well as retrieving candidates from persisted pools, ensuring better performance and responsiveness in music recommendations. This update aims to streamline agent logic and enhance the overall recommendation system.

Add autopep8 as a dependency for code formatting - Updated pyproject.toml to include autopep8 version 2.3.2 for improved code style consistency. Modified uv.lock to reflect the new dependency and its requirements. This update aims to enhance code maintainability and adherence to style guidelines.

Update .gitignore and remove obsolete cleanup documentation - Added `.gradio` and `tests/data/cache` to `.gitignore` to prevent unnecessary file tracking. Deleted outdated cleanup documentation files (`AGENT_CLEANUP_COMPLETION.md` and `CLEANUP_PLAN.md`) to streamline the codebase and remove obsolete references. This cleanup supports ongoing refactoring efforts and enhances overall project maintainability.

Remove obsolete test files and enhance agent initialization - Deleted unused test files `test_backend_fixes.py` and `test_query_fix.py` to streamline the codebase. Updated agent initialization in `EnhancedRecommendationService` to include rate limiting for improved API management and performance. This cleanup supports ongoing refactoring efforts and enhances the overall structure of the project.

Remove obsolete test files and refactor agent imports - Deleted unused test files for `test_fix.py` and `test_smart_context.py`. Updated agent imports in `__init__.py` and other files to streamline the codebase and improve maintainability. This cleanup supports ongoing refactoring efforts and enhances the overall structure of the project.