mq-mcp v1.8.0 — Complete v1.6.0 generated artifacts

What's new

• Added review_engine/generated_artifacts.py with two builders:
  • build_rich_architecture_map() — writes generated/architecture/architecture_map.json (schema architecture_map.v1): per-file role, public symbols, last review timestamp, hub score.
  • build_ownership_map() — writes generated/architecture/ownership_map.json (schema ownership_map.v1): per-file author, change frequency, last modified. Scans last 200 commits.
• Extended build_repo_context (Class C) to call both builders after the callgraph build.
• Updated docs/RUNTIME_CONTRACT.md — added Generated artifacts section under Context model.
• Tool count: 75 → 76. All v1.6.0 ROADMAP items now marked done.