Cover the stdio adapter: local-mode env bootstrap (OAuth off, API-key gate off,
per-user audit path), missing-env failure, PAT owner resolution, and dispatch
(unknown tool, write-mode policy denial, and the happy path pinning request
context to the PAT owner via the shared registry). Tidy the boundary-test
assertion so ruff and black agree.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>