feat(player): add speed control with popup menu and CSS theming - #241

Summary

• Adds a playback speed control to the <hyperframes-player> controls bar with a popup menu (0.25x, 0.5x, 1x, 1.5x, 2x, 4x)
• Customizable speed presets via speed-presets attribute (e.g. speed-presets="0.5,1,2")
• Full CSS custom property theming — consumers can override colors, fonts, spacing, and menu styles from outside the shadow DOM
• Dispatches ratechange event when speed changes
• Fixes package.json export condition ordering (script before import/require)

Customization

Custom presets:

<hyperframes-player controls speed-presets="0.5,1,1.5,2"></hyperframes-player>

CSS theming:

hyperframes-player {
  --hfp-accent: #ff6b6b;
  --hfp-controls-bg: linear-gradient(transparent, rgba(0,0,0,0.9));
  --hfp-font: "Inter", sans-serif;
  --hfp-menu-bg: rgba(15,15,15,0.95);
}

Test plan

• bun run test — 11/11 tests pass (4 new for SPEED_PRESETS + formatSpeed)
• bun run build — full monorepo build passes
• Pre-commit hooks pass (lint, format, typecheck, commitlint)
• Manual: open test page, click speed button, verify popup menu appears
• Manual: select different speeds, verify playback rate changes
• Manual: verify menu closes on outside click
• Manual: verify CSS custom properties override styles