Revamp GitHub Pages with full-width design and NASA globe

[schlunsen]

Summary

• Full-width desktop layout — replaces narrow 1200px containers with fluid edge-to-edge grids using clamp() padding
• Proper site header — fixed nav with section links, active highlighting, mobile hamburger, green Download button, and GitHub pill
• NASA Blue Marble globe — custom GLSL day/night shader blending earth_daymap.jpg + earth_night.jpg (same textures as the Mac app), with atmosphere fresnel glow and star field
• Platforms section — side-by-side showcase of the Rust CLI (small footprint, cross-platform, SSH-friendly) and the native macOS SwiftUI app (3D globe, menu bar widget, DMG installer)
• Installation + Usage merged — side-by-side two-column layout on desktop
• Bug fixes — fixed broken OG image path, added .nojekyll, added Three.js import map to resolve bare specifier error

Test plan

• Open docs/index.html locally (python3 -m http.server 8000 from docs/)
• Verify globe renders with NASA textures and day/night shading
• Check header nav links scroll to correct sections with offset
• Test mobile hamburger menu at <600px viewport
• Verify all screenshots load from raw.githubusercontent.com
• Check Download buttons link to latest GitHub release
• Confirm no console errors (especially the previous Three.js import error)

🤖 Generated with Claude Code