Add CLAUDE.md with repo overview and T3 FAQ docs

[matteo-tousignant17]

Documents the monorepo structure, T3 axioms, common commands, and the full FAQ from www/src/pages/en/faq.mdx for quick reference.

https://claude.ai/code/session_01GFwCaeXcVGPxVop2gfvUpK

Closes #

✅ Checklist

• I have followed every step in the contributing guide (updated 2022-10-06).
• The PR title follows the convention we established conventional-commit
• I performed a functional test on my final commit

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Changelog

[Short description of what has changed]

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Screenshots

[Screenshots]

💯

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Project	Deployment	Actions	Updated (UTC)
create-t3-app	Ready	Preview, Comment	May 29, 2026 4:35am

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