Add HyperFrames skills (from heygen-com/hyperframes, Apache-2.0)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FXVsD1DgdzZLiPuwtKzMSY

.claude/skills/hyperframes-cli/references/beats.md

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+# Generate a project beat grid
+
+Use `hyperframes beats` when an existing HyperFrames project needs the Studio-compatible beat file for its music track. This is a CLI utility, not a complete video workflow.
+
+```bash
+npx hyperframes beats
+npx hyperframes beats ./my-video
+npx hyperframes beats ./my-video --json
+```
+
+The project must contain a local music `<audio>` source. Mark it with `data-timeline-role="music"`; an id containing `music`, `bgm`, or `soundtrack` is also recognized. The command decodes that file with ffmpeg, tracks its beats, and writes `beats/<audio-relative-path>.json`.
+
+If the track has no steady beat, the command fails and writes nothing. If ffmpeg is missing, run `npx hyperframes doctor`.
+
+For a whole video cut to a music track, see `/hyperframes` → `references/film.md`.