Add Auth0 to provider list

[btiernay]

Summary

After addressing the open issues, this PR adds Auth0 to the documented list of identity providers tested with MCP Auth.

What’s included:

• Updates to the Provider list page to include Auth0, with ✅ for dynamic client registration and ⚠️ for resource indicator support.
• Footnote explains that while Auth0 supports multi-resource refresh tokens (MRRT), it does not support full RFC 8707 resource indicators.
• Verified that Auth0 passes all compatibility checks via the embedded <TestProvider /> tool.
• Minor clarification added to the dynamic client registration FAQ to guide users based on their use case (internal vs. public MCP servers).

This helps users better evaluate which providers are plug-and-play with MCP Auth and what workarounds or limitations to expect.

Open to feedback or additional notes on edge-case behavior.

Test plan

Verified provider is displayed correctly in the documentation:

And with the test tool:

[cloudflare-workers-and-pages]

Deploying mcp-auth-docs with    Cloudflare Pages

Latest commit:	4d52f0c
Status:	✅  Deploy successful!
Preview URL:	https://dd5c910a.mcp-auth-docs.pages.dev
Branch Preview URL:	https://docs-auth0-provider-listing.mcp-auth-docs.pages.dev

View logs

[xiaoyijun]

Hi @btiernay , merging is blocked because your commits do not have verified signatures.
Please see the instructions here to sign your commits:
https://docs.github.com/en/authentication/managing-commit-signature-verification/about-commit-signature-verification

[xiaoyijun]

Hi @btiernay , I’ve resolved the issue by re-signing the commits during a rebase, so merging is now unblocked.
Just as a heads-up, our main branch requires all commits to be signed. For future contributions, it would be great if you could set up commit signing as mentioned in the link in the previous comment.

[btiernay]

Thanks! I have commit signing enabled, but something got reverted for this repo. Will fix!

[nicotriballier]

FYI the list to the compatible providers above is broken, and looks like it got moved to https://mcp-auth.dev/provider-list for whoever lands on that thread. thx!