- Replace deprecated FastAPI @app.on_event('startup'/'shutdown') with
  the lifespan context manager (required for FastAPI 0.95+)
- Remove scratch_failing.py leftover debug file from repo root
- Remove hardcoded fake ANTHROPIC_API_KEY/ANTHROPIC_BASE_URL from
  cli/__init__.py (credential leak in source code)
- Fix _rust_bridge.py: RUST_AVAILABLE was unconditionally True even
  when the compiled extension was absent; now correctly probes the
  import at module load time and sets the flag accordingly, so callers
  can branch without hitting an ImportError at runtime
- Add requirements.txt for plain pip installs (no uv required)
- Update LICENSE from Apache 2.0 to MIT
- Update pyproject.toml license classifier to MIT
- Rewrite README.md as a professional, structured document with
  badges, feature list, installation steps, SDK/CLI/API usage
  examples with code snippets, tech stack table, and configuration
  reference