chore: add CodeRabbit configuration

[frederikprijck]

Summary

• Add .coderabbit.yaml with review guidance tailored to the auth0-fastify monorepo, modeled on the auth0-nuxt config.
• Organized into two parts so it can be shared across our sibling TS auth SDKs:
  • [BASELINE] — generic to any TS auth SDK: review behavior, path filters, TS rules, an auth security review block (secrets/token leakage, cookie flags, state/nonce/PKCE, open redirects, token validation, timing-safe comparison, prototype pollution, fail-closed auth), test/example/CI guidance, and tools. Kept verbatim from auth0-nuxt.
  • [FASTIFY] — repo-specific: the Fastify v5 plugin + inline OAuth/OIDC route handlers (login/callback/logout/backchannel + connect/unconnect) with toSafeRedirect/createRouteUrl and appBaseUrl header-inference scrutiny; toSafeRedirect open-redirect guard; the FastifyCookieHandler secure-cookie defaults; and the auth0-fastify-api requireAuth middleware (fail-closed, RS256/HS* rejection, scope 403 / token 401 semantics, DPoP modes, WWW-Authenticate escaping).
• Enables eslint, gitleaks, semgrep, actionlint, markdownlint, languagetool; excludes dist/, coverage/, *.d.ts, and the lockfile; skips release PRs.

Test plan

• CodeRabbit picks up the config on this PR and posts a review

[coderabbitai]

Warning

Review limit reached

@frederikprijck, we couldn't start this review because you've reached your PR review rate limit.

More reviews will be available in 24 minutes and 38 seconds. Learn how PR review limits work.

Your organization has run out of usage credits. Purchase more in the billing tab.

⌛ How to resolve this issue?

After more reviews become available, a review can be triggered using the @coderabbitai review command as a PR comment. Alternatively, push new commits to this PR.

We recommend that you space out your commits to avoid hitting the rate limit.

🚦 How do rate limits work?

CodeRabbit enforces hourly rate limits for each developer per organization.

Our paid plans include higher PR review limits than trial, open-source, and free plans. In all cases, reviews become available again over time. During sustained high-volume PR review activity, CodeRabbit may temporarily slow when the next review becomes available.

Please see our Fair Usage Limits Policy for further information.

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: b9f0f57e-0163-49db-aac7-1e0e66aebd58

📥 Commits

Reviewing files that changed from the base of the PR and between 478cb01 and d630a32.

📒 Files selected for processing (1)

• .coderabbit.yaml

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch chore/add-coderabbit-config

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}