fix: recover neo4j graph connections

fix(api): support Aura Neo4j env names

feat(eval): RAGAS evaluation framework + RAG pipeline improvements

test(nodes): update patch targets to civicsetu.retrieval.reranker

fix: relax reranker thresholds to prevent aggressive chunk filtering

test: assert reranker_filtered log event counts in test_reranker_filtered_count_logged

feat: filter reranker output by score threshold + score-gap brake

feat: add _apply_score_gap() helper for dynamic top-k reranking

test: fix MagicMock class mutation in test_get_ranker_uses_settings_model

feat: make _get_ranker() use settings.reranker_model

test: verify reranker settings env-var override paths

feat: add reranker_model, score_threshold, score_gap settings

chore: bump to v1.0.0 + update docs with Vercel live URL

feat: decouple frontend + multi-turn conversation + graph explorer + CAG layer

test(4.3): add unit test suite — 31 tests, 0→full coverage on critical paths

feat: Phase 0 complete — RERA RAG pipeline with FastAPI