feat(memes): full-bleed hero with Bayer dither image cycling

[h0lybyte]

Summary

• Replace Starlight's default hero with a custom full-viewport magazine-style hero section
• AstroHeroSection.astro renders static HTML at build time (zero JS, instant paint) with background image, gradient overlay, animated text, and CTA buttons
• HeroDitherCycle.tsx is an O(1) React hydration island (renders null) that cycles unsplash backgrounds using an 8x8 Bayer ordered-dither dissolve on a quarter-resolution canvas with image-rendering: pixelated
• PageTitle.astro override suppresses Starlight's h1 and content-panel padding on splash pages for true edge-to-edge layout with zero layout shift
• Unsplash image rotation managed via a simple array of photo IDs

Test plan

• Verify hero fills full viewport with no side dead space on mobile and desktop
• Wait ~8s and confirm Bayer dither dissolve transition between images
• Scroll down and verify hero fades out smoothly
• Confirm non-splash pages (e.g. guides) still render h1 and normal layout
• Resize browser and confirm canvas redraws correctly

🤖 Generated with Claude Code

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None