docs: add Claude Design HyperFrames entry point (#353)

## Summary
- add a GitHub-hosted `claude-design-hyperframes` skill entry point that tells Claude Design to fetch the upstream HyperFrames skills tree
- add a dedicated Claude Design docs guide and link it from quickstart, prompting, and the README
- fix `@hyperframes/player` CDN docs to show a working ESM include and the explicit global-build fallback

## Verification
- `bunx oxfmt --check README.md docs/docs.json docs/guides/prompting.mdx docs/packages/player.mdx docs/quickstart.mdx packages/player/README.md docs/guides/claude-design.mdx skills/claude-design-hyperframes/SKILL.md`
- `bun run lint:skills`
- `bunx mintlify broken-links`
- browser-engine screenshots captured with Playwright CLI for the changed docs/source surfaces:
  - `/tmp/hyperframes-pr-artifacts/claude-design-guide-source.png`
  - `/tmp/hyperframes-pr-artifacts/player-docs-source.png`

## Notes
- `mintlify dev`, `mintlify validate`, and `mintlify export` stalled in this environment during preview/bootstrap, so I used the broken-links check plus screenshot-based browser fallback instead of claiming a full rendered-site pass.
- The GitHub entry-point setup reflects current Claude Design behavior discussed in the task: point Claude Design at the repo-hosted skill URL rather than a ZIP upload flow.

packages/player/README.md

@@ -11,7 +11,13 @@ npm install @hyperframes/player
 Or load directly via CDN:
 
 ```html
-<script src="https://cdn.jsdelivr.net/npm/@hyperframes/player"></script>
+<script type="module" src="https://cdn.jsdelivr.net/npm/@hyperframes/player"></script>
+```
+
+If you need a classic `<script>` tag instead of ESM, use the explicit global build:
+
+```html
+<script src="https://cdn.jsdelivr.net/npm/@hyperframes/player/dist/hyperframes-player.global.js"></script>
 ```
 
 ## Usage