fix(cli): remove sync and serve commands referencing non-existent modules

feat(eval): add --pipeline flag for full pipeline eval (retriever + Gemini filter)

feat(eval): add cli.py eval command with diff and history

fix: add dotenv loading, enrichment retry logic, and graceful error handling

fix: address code review issues (theme/css, reranker condense, cli serve)

feat: vectorize command builds BM25 index alongside ChromaDB, remove segments

feat: expand enrichment prompt with themes, countries, event_period, media_type, is_subject + cache invalidation