feat: open-source template refactor

- Extract content to src/config/profile.js (single-file customization)
- Add Apache-2.0 LICENSE, CONTRIBUTING.md, robots.txt
- Add GitHub Pages auto-deploy workflow
- Update package.json: private=false, license, homepage
- Add SEO/Open Graph meta tags to index.html
- Rewrite README.md with Quick Start guide
- Update .gitignore: AI tooling, caches, deployment state

CONTRIBUTING.md

@@ -0,0 +1,9 @@
+# Contributing
+
+1. Fork the repository.
+2. Customize `src/config/profile.js` with your profile details.
+3. Push your branch and open a pull request.
+
+Keep each pull request focused on one feature or fix. Use GitHub Issues to report bugs or propose features.
+
+For other questions, contact [[email protected]](mailto:[email protected]).