feat(skills): design.md integration, shared video references, Claude Design gaps (#549)

## What

Major skill infrastructure update: design.md support, shared video-composition references, and creative direction patterns extracted from website-to-hyperframes into the base hyperframes skill.

## Changes

### design.md Integration (lightweight)
- Step 0a reads any format design.md (YAML, prose, tables) — no format mandate
- Brand colors/fonts are strict; video layout adapts per video-composition.md
- Font warning gate: warns user if design.md names fonts without local .woff2 files
- Design picker generates spec-compliant design.md with YAML frontmatter + prose
- Picker generates contextual options from user's prompt (3-4 architectures, 5-6 palettes, 3 type pairings)

### Shared Video References (extracted from website-to-hyperframes)
- `video-composition.md` — density, scale, color presence, frame composition rules. Light canvas guidance (don't override user palette). **Always read.**
- `beat-direction.md` — per-beat planning (concept → mood → choreography verbs → transition), rhythm templates by video type
- `techniques.md` — 11 visual techniques with code patterns (SVG drawing, Canvas 2D, kinetic type, Lottie, etc.)
- `narration.md` — pacing, tone, script structure, number pronunciation, hooks
- `motion-principles.md` — gained image motion treatment + load-bearing GSAP rules

### Claude Design Transfer Brief (6 gaps applied)
1. Discovery step for exploratory requests (audience, platform, priority, variations)
2. Anti-scope-creep: "build what was asked, every element earns its place"
3. Read-source discipline: "read actual files, don't guess"
4. Rhythm planning: declare scene rhythm before implementing
5. Variations as first-class output for exploratory requests
6. Two-phase verification: fast checks block, slow checks parallel

### Prompt Expansion Updated
- Uses beat-direction format (concept → mood → verbs → depth layers)
- Rhythm declaration before scene breakdown
- References video-composition.md and beat-direction.md

### Key Design Decision
**design.md = brand truth, not video layout spec.** Background color is strict from design.md (don't switch light to dark). Video-composition rules teach how to make any palette work cinematically.

## Files Changed (16)

**New shared references:**
- `skills/hyperframes/references/video-composition.md`
- `skills/hyperframes/references/beat-direction.md`
- `skills/hyperframes/references/techniques.md`
- `skills/hyperframes/references/narration.md`

**Updated:**
- `skills/hyperframes/SKILL.md` — discovery, anti-scope-creep, rhythm, variations, two-phase verify, new references
- `skills/hyperframes/references/prompt-expansion.md` — beat-direction format
- `skills/hyperframes/references/motion-principles.md` — image treatment + GSAP rules
- `skills/hyperframes/references/design-picker.md` — contextual generation
- `skills/hyperframes/visual-styles.md` — YAML token blocks per preset
- `skills/hyperframes/house-style.md` — design.md precedence
- `skills/hyperframes/templates/design-picker.html` — spec-compliant output
- `skills/website-to-hyperframes/references/*` — now reference shared files

## Test plan

- [x] Design picker generates and serves correctly
- [x] Picker output is spec-compliant design.md
- [x] Composition built from picker design.md renders in Studio
- [x] Before/after eval: 4 topics × 2 versions showing skill guidance impact
- [x] Light canvas compositions respect user palette (don't switch to dark)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

skills/website-to-hyperframes/references/step-6-build.md

@@ -5,7 +5,7 @@
 - **DESIGN.md** — your color palette, fonts, components, and Do's/Don'ts. Every composition must use EXACT hex colors and font families from this file. If it says "white backgrounds" — use white, not dark.
 - **STORYBOARD.md** — the beat-by-beat plan you're executing. Each beat specifies assets, animations, transitions, and which techniques to use.
 - **`capture/extracted/asset-descriptions.md`** — when the storyboard assigns an asset to a beat, re-read the description to understand what it shows and how to position/style it correctly.
-- **[techniques.md](techniques.md)** — code patterns for the 10 visual techniques. When the storyboard says "SVG path drawing" or "per-word kinetic typography" — read the code pattern from this file and adapt it.
+- **[techniques.md](../../hyperframes/references/techniques.md)** — code patterns for the 10 visual techniques. When the storyboard says "SVG path drawing" or "per-word kinetic typography" — read the code pattern from this file and adapt it.
 - **transcript.json** — word-level timestamps that drive scene durations.
 
 **Split the work: spawn a sub-agent for each beat.** By this step your context is full of captured data, DESIGN.md, SCRIPT, STORYBOARD, and transcript. Building compositions on top of all that means the detailed rules below compete with thousands of tokens of prior work. Each sub-agent gets a fresh context focused on one beat — dramatically better output.