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.

Remove obsolete test scripts for follow-up behavior, detection fix, history filtering, hybrid context, Kendrick follow-up, simple extraction, and state management - Deleted multiple test files to streamline the codebase and eliminate unused tests. This cleanup supports ongoing refactoring efforts and enhances overall project maintainability.