feat: implement async-safe rate limiting (Phase 17) (#40)

refactor(tests): add type annotations and clean up test functions

feat(search): implement ClinicalTrials.gov filtering (Phase 03)

feat(search): implement PubMed query preprocessing (Phase 02)

refactor(tools): replace BioRxiv with Europe PMC (Phase 01)

fix: address CodeRabbit review feedback

feat: add demo mode warnings and BYOK (Bring Your Own Key) support

feat: Phase 11 bioRxiv Preprint Integration (#19)

refactor: address CodeRabbit nitpicks for Phase 10

feat: Implement Phase 10 (ClinicalTrials.gov) with requests

feat: Complete Phase 9 Source Cleanup (Remove WebTool) (#14)

feat(phase2): implement search slice (PubMed, Web, Orchestrator) (#4)

feat(phase1): Foundation & Tooling complete