Adds MCP FGA quickstart

[jtemporal]

Adds a new quickstart guide "Secure MCP Server with Auth0 FGA" demonstrating fine-grained authorization for MCP tools using Auth0 FGA/OpenFGA.

New files:

• fga-cli-installation.mdx - FGA CLI setup
• fga-store-setup-overview.mdx - FGA provider overview
• setup-fga-store-cli.mdx - Store setup (Auth0 FGA vs OpenFGA tabs)
• fga-model-explanation.mdx - Authorization model docs
• create-env-file-fga.mdx - Environment configuration
• managing-permissions.mdx - Helper scripts documentation
• auth4genai/mcp/get-started/secure-mcp-server-with-auth0-fga.mdx - Quickstart content

Updated files:

• auth4genai/docs.json - Added new quickstart to navigation
• auth4genai/mcp/get-started/overview.mdx - Added card

Checklist

• I have added documentation for new/changed functionality in this PR or in auth0.com/docs
• All active GitHub checks for tests, formatting, and security are passing
• The correct base branch is being used, if not the default branch

[github-actions]

Summary

Status	Count
🔍 Total	18
✅ Successful	5
⏳ Timeouts	0
🔀 Redirected	5
👻 Excluded	6
❓ Unknown	0
🚫 Errors	2
⛔ Unsupported	0

Errors per input

Errors in auth4genai/mcp/get-started/secure-mcp-server-with-auth0-fga.mdx

• [ERROR] https://docs.fga.dev/authorization-concepts#what-is-relationship-based-access-control | Cannot find fragment: Fragment not found in document. Check if fragment exists or page structure

Errors in auth4genai/snippets/mcp/get-started/fga/fga-model-explanation.mdx

• [ERROR] https://docs.fga.dev/authorization-concepts#what-is-relationship-based-access-control | Cannot find fragment: Fragment not found in document. Check if fragment exists or page structure

Redirects per input

Redirects in auth4genai/mcp/get-started/call-your-apis-on-users-behalf.mdx

• [200] https://auth0.com/ai/docs | Redirect: Followed 1 redirect resolving to the final status of: OK. Redirects: https://auth0.com/ai/docs --> https://auth0.com/ai/docs/intro/overview

Redirects in auth4genai/mcp/get-started/overview.mdx

• [200] https://auth0.com/ai/docs | Redirect: Followed 1 redirect resolving to the final status of: OK. Redirects: https://auth0.com/ai/docs --> https://auth0.com/ai/docs/intro/overview

Redirects in auth4genai/mcp/get-started/secure-mcp-server-with-auth0-fga.mdx

• [200] https://auth0.com/ai/docs | Redirect: Followed 1 redirect resolving to the final status of: OK. Redirects: https://auth0.com/ai/docs --> https://auth0.com/ai/docs/intro/overview
• [200] https://openfga.dev/docs | Redirect: Followed 1 redirect resolving to the final status of: OK. Redirects: https://openfga.dev/docs --> https://openfga.dev/docs/

Redirects in auth4genai/snippets/mcp/get-started/fga/fga-store-setup-overview.mdx

• [200] https://fga.dev/ | Redirect: Followed 2 redirects resolving to the final status of: OK. Redirects: https://fga.dev/ --> https://auth0.com/developers/lab/fine-grained-authorization --> https://auth0.com/fine-grained-authorization
  Full Github Actions output

[mikemimik]

LGTM

Approved changes for:

• docs.json
• auth4genai/snippets/*