Add AGENTS.md for dev environment setup

[andreafuturi]

Summary

Adds AGENTS.md with Cursor Cloud-specific development environment instructions for this portfolio site.

What's included

• Project overview (Deno + Vite/Preact portfolio site)
• Runtime requirements (Deno, Node.js/npm)
• Dev commands reference (pointing to package.json scripts)
• Known gotchas (Deno 2.x --unstable warning, missing client source for Vite, no linter/tests configured)

Development Environment Verification

The dev environment was fully set up and verified:

• Deno server (npm run dev-server) running on port 8000
• Portfolio main page loads with interactive SVG quasiperiodic pattern
• /grazie thank-you page serves correctly
• Static assets (JS, SVG, images) all serve with correct content types

Demo

demo_portfolio_site_interaction.mp4

Portfolio welcome screen and interactive pattern:
Welcome screen
SVG pattern after clicking Continue
Grazie thank-you page

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