fix(server): cap list_recent days at 365

fix: harden corpus sync, remove request-time file races, reject blank queries

feat: mount per-corpus MCP servers with search, read, citation, and recency tools

feat: hybrid BM25 + embedding search with reciprocal rank fusion

feat: load corpus metadata, markdown paths, and citation graph

fix: satisfy ruff lint and format checks

feat: project scaffold and corpus git sync