feat: add ui_design_specialist (Phase 3 UI Design) v0.2.0

- New specialist: ui_design_specialist with iterative mockup dialog
- New Phase 3 (UI Design) between Architecture and Implementation
- Relay model: orchestrator passes responses verbatim in Phase 3
- Cost-control exception for UI Design phase (unlimited subagent calls)
- Webspace mockup workflow with cache-buster and obscure dirs
- UX states coverage (loading, empty, error, partial)
- WCAG 2.1 AA accessibility guidelines
- Design tokens (CSS custom properties) in design system
- Component states (hover, focus, active, disabled, loading, error)
- Sitemap/wireframe before mockups for complex UIs
- Real content strategy (no Lorem Ipsum)
- Form validation UX in mockups
- Dark mode and i18n support (optional)
- Design handoff support (specialist available during implementation)
- Skip mechanism for non-UI projects
- Mockup state file for context compression recovery
- Multi-page mockup strategy with index.html
- task_graph.json mockup references
- Plugin version: 0.1.14 -> 0.2.0
- 47 files changed across 7 implementation blocks
- 3 review rounds with 41 corrections integrated

help/testing/validation.md

@@ -10,11 +10,15 @@ tags: ['testing', 'validation', 'ci']
 Run the project's existing test and build tooling to validate a change, without inventing new commands.
 
 ## When to Use
-- After any implementation block
+- After any implementation block (Phase 4)
 - Before declaring a feature complete
 - Before a release
 - When verifying a bug fix
 
+## Phase Context
+Full phase sequence: 1 (Intake) → 2 (Architecture) → 3 (UI Design) → 4 (Implementation) → 5 (Test) → 6 (Runtime) → 7 (Deployment) → 8 (Release)
+Test validation occurs in Phase 5, after Implementation (Phase 4). UI Design (Phase 3) produces mockups and design specs that guide implementation.
+
 ## When Not to Use
 - When no test framework exists (create one first, see implementation_engineer)
 - For purely documentation changes (no test needed)