feat(skills): add design-motion-principles from kylezantos

Motion/animation design skill with 3-designer lens (Emil Kowalski,
Jakub Krehel, Jhey Tompkins). Two modes: Create and Audit.
Complements frontend-design (broad) with deep motion expertise.

Integration points:
- skills-external/design-motion-principles/ — skill files + references
- link.sh EXTERNAL_SKILLS — symlink to ~/.claude/skills/
- install-plugins.sh step 8c — presence check
- update-all.sh step 7.2 — sync from GitHub
- profiles: design, full, web, web-full — listed as external
- plugin-advisor — decision table, recommended sets, conditional rules
- design-gate — symlink check + non-blocking warning if missing

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/design-gate.md

@@ -27,14 +27,15 @@ Check BOTH the task description AND the filesystem:
 
 If **at least one signal** is detected:
 
-1. Check if `ui-ux-pro-max` and `frontend-design` are active:
+1. Check if `ui-ux-pro-max`, `frontend-design`, and `design-motion-principles` are active:
    ```bash
    source "$HOME/.claude/lib/detect-plugins.sh"
    detect_uiux_pro_max && echo "ui-ux-pro-max: ACTIVE" || echo "ui-ux-pro-max: INACTIVE"
    [ -L "$HOME/.claude/skills/frontend-design" ] && echo "frontend-design: ACTIVE" || echo "frontend-design: INACTIVE"
+   [ -L "$HOME/.claude/skills/design-motion-principles" ] && echo "design-motion-principles: ACTIVE" || echo "design-motion-principles: INACTIVE"
    ```
 
-2. If **both ACTIVE** → proceed silently. Design context is fully available.
+2. If **all three ACTIVE** → proceed silently. Design context is fully available.
 
 3. If **ui-ux-pro-max INACTIVE** → ask the user:
    ```
@@ -51,6 +52,12 @@ If **at least one signal** is detected:
    Install: run install-plugins.sh or symlink skills-external/frontend-design to ~/.claude/skills/frontend-design
    ```
 
+5. If **design-motion-principles INACTIVE** and task mentions animation/motion/transition → warn (non-blocking):
+   ```
+   ℹ️ design-motion-principles skill not installed — motion design guidelines unavailable.
+   Install: run install-plugins.sh or symlink skills-external/design-motion-principles to ~/.claude/skills/design-motion-principles
+   ```
+
 ## IMPORTANT
 
 - This gate adds ~5 seconds overhead. Worth it for design quality.

lib/profiles/design.profile

@@ -20,6 +20,7 @@ plan-ceo-review
 # External: design skills
 emil-design-eng                   external
 frontend-design                   external
+design-motion-principles          external
 
 # Plugin (auto-toggle)
 ui-ux-pro-max                     plugin@ui-ux-pro-max-skill

lib/profiles/full.profile

@@ -75,6 +75,7 @@ guard
 # === External + plugin + MCP =========================================
 emil-design-eng                   external
 frontend-design                   external
+design-motion-principles          external
 ui-ux-pro-max                     plugin@ui-ux-pro-max-skill
 pr-review-toolkit                 plugin@claude-code-plugins
 magic                             mcp

lib/profiles/web-full.profile

@@ -46,6 +46,7 @@ qa-only
 # === External + plugin + MCP =========================================
 emil-design-eng                   external
 frontend-design                   external
+design-motion-principles          external
 ui-ux-pro-max                     plugin@ui-ux-pro-max-skill
 magic                             mcp
 

lib/profiles/web.profile

@@ -35,6 +35,7 @@ validate                          personal
 # External: design skills
 emil-design-eng                   external
 frontend-design                   external
+design-motion-principles          external
 
 # Plugin: UI/UX intelligence (auto-toggle)
 ui-ux-pro-max                     plugin@ui-ux-pro-max-skill