docs: add React Router quickstart and SDK library entry

[yogeshchoudhary147]

Adds documentation for @auth0/auth0-react-router.

Changes

• New quickstart page: main/docs/quickstart/webapp/react-router.mdx — covers setup, login/logout, protected routes, and user profile for React Router framework-mode apps (v7 or later).
• Added to the "Regular Web App" navigation group in main/config/navigation/quickstarts.json.
• Added SectionCard to main/docs/quickstarts.mdx and main/docs/libraries.mdx.
• Added "React Router" entry to sdkCardInfo in main/snippets/sdks/versions.mdx.
• Added react-router.svg to main/docs/images/icons/light/ and dark/.

Checklist

• I've read and followed CONTRIBUTING.md.
• I've tested the site build for this change locally.
• I've made appropriate docs updates for any code or config changes.

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Project	Status	Preview	Updated
auth0	🟢 Ready	View Preview	Sep 17, 2026, 5:51 PM

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[github-actions]

Summary

Status	Count
🔍 Total	101
🔗 Unique	85
✅ Successful	96
⏳ Timeouts	0
🔀 Redirected	4
👻 Excluded	2
❓ Unknown	0
🚫 Errors	3
⛔ Unsupported	0

Errors per input

Errors in main/docs/libraries.mdx

• [ERROR] </docs/authenticate/login/auth0-universal-login/universal-login-vs-classic-login/universal-experience#universal-login-experience> (at 80:28) | Cannot find fragment

Errors in main/snippets/sdks/versions.mdx

• [404] https://github.com/auth0-samples/auth0-hono-sample/tree/master/01-Login (at 465:17) | Rejected status code: 404 Not Found
• [404] https://github.com/auth0-samples/auth0-nuxt-samples (at 230:17) | Rejected status code: 404 Not Found

Full Github Actions output

Run on commit 9b9b931.