v0.5.0

Added

• Neighbor ranking option for query expansion: HTTP /mcp/query accepts neighbor_ranking ("degree" or "none"); default is degree-based ranking by node degrees.
• Pipeline CLI flag --content-hash-ids and CONTENT_HASH_IDS env var to generate stable content-hash IDs when no front-matter id is present.
• Tests: coverage for ranking modes, CLI flag/env handling, rollback paths in HypergraphWriter, FTS creation, and PRAGMA error handling.

Changed

• SQLite ingest tuning: added page size, cache, and mmap PRAGMAs for faster local builds; documented in docs/pipeline-optimization.md.
• Docs: updated README, backend, and pipeline docs to reflect new options and flows; ensured Markdown formatting and lint.
• QA: expanded test suite; overall coverage ~98%.