Add Eleventy blog and GitHub Pages deployment

[BlackFrameAI]

Summary

• introduce an Eleventy-powered journal with layouts, metadata, dark/light theming, RSS feed, and sitemap while preserving the existing splash page via passthrough copy
• seed the initial “Birth of Vibe Coding” post, shared assets, and raw lab log links under /posts/, /assets, and /logs
• configure a GitHub Actions workflow to build the Eleventy site and deploy the _site output to GitHub Pages

Testing

• npm run build (fails locally: Eleventy CLI is unavailable in the sandbox due to blocked npm registry)

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https://chatgpt.com/codex/tasks/task_e_68f538677b5c83289b989d620a22967e