Fix stale OAuth client registrations

[lipluscodex]

Closes #176
ランダムなlocalhost callback portに対してcached Dynamic Client Registrationのredirect URI互換性を検証し、不一致時はauthorization前に再登録します。
回帰テストを通常CIへ接続し、要求仕様とclient proxy READMEを同期します。

Release type: patch

[cloudflare-workers-and-pages]

Deploying with    Cloudflare Workers

The latest updates on your project. Learn more about integrating Git with Workers.

Status	Name	Latest Commit	Updated (UTC)
✅ Deployment successful! View logs	github-rag-mcp	1c193ea	Jul 29 2026, 03:36 AM

[lipluscodex]

Self-review: PASS

• Acceptance criteria: cached registration is reused only when a non-empty client_id and registered redirect URI set cover every callback URI requested by the current OAuth flow; stale-port, partial, and malformed caches all force re-registration.
• Preserved constraints: random callback port and PKCE S256 remain unchanged; no credential or registration values are logged.
• Verification: proxy 5/5 tests, Worker 75/75 tests, schema drift, TypeScript, dry deploy, package dry-run, and all PR checks passed.
• Docs/CI: English/Japanese requirements, proxy README, and the normal CI path are synchronized.
• Scope deviations: none. The CI file was added to the issue target list before commit so the new regression suite cannot silently fall out of routine checks.
• Next step: auto mode, patch classification; proceed to squash merge after confirming mergeable state.