docs: add launch publicity kit

[jasonsuhari]

Summary

• add a 13-second HyperFrames launch teaser, poster, reproducible source, and stable render instructions
• add ready-to-publish copy for Show HN, Reddit, Product Hunt, social, Discord, and a complete technical article draft
• update the README and GitHub Pages hero to use the new teaser

Validation

• HyperFrames lint: 0 errors, 0 warnings
• HyperFrames validate: no console errors; 28 text elements pass WCAG AA
• visually inspected rendered frames at 1.5s, 6.5s, 10.0s, and 12.7s
• cargo test: 116 passed, 1 ignored
• npm run test:launcher: 8 passed
• npm pack --dry-run --ignore-scripts

Closes #150