feat(agents): replace Design System Specialist with UI/UX Designer Agent

- Remove project-specific design-system-specialist.json
- Add universal ui-ux-designer.json v1.1.0
- Update all references and documentation

Shifts focus from design system validation to universal design principles
and UX best practices for better portability across projects.

Breaking: Design System Specialist → UI/UX Designer Agent

close #17

Author: wishket-pjw

.ai-rules/agents/README.md

@@ -19,7 +19,7 @@ Unified specialist agents organized by domain:
 
 - **Accessibility** (`accessibility-specialist.json`)
 - **Architecture** (`architecture-specialist.json`)
-- **Design System** (`design-system-specialist.json`)
+- **UI/UX Design** (`ui-ux-designer.json`)
 - **Documentation** (`documentation-specialist.json`)
 - **Performance** (`performance-specialist.json`)
 - **Security** (`security-specialist.json`)
@@ -53,8 +53,8 @@ Unified specialist agents organized by domain:
 - **Server-First**: Defaults to Server Components, uses Client Components only when needed
 - **Server Actions**: Prefers Server Actions over API routes for mutations
 - **HTML/CSS First**: Solves with HTML/CSS before JavaScript
-- **Design System First**: Always prefers project design system components
-- **ClassName Composition**: Uses twJoin/twMerge, never string concatenation
+- **Design Principles**: Visual hierarchy, CRAP principles, UX laws
+- **User Experience**: User flow optimization, interaction patterns
 - **Accessibility**: WCAG AA compliance with semantic HTML
 - **SEO**: Comprehensive metadata and structured data
 
@@ -194,7 +194,7 @@ Unified specialist agents organized by domain:
 - Security: XSS/CSRF, authentication/authorization (Reference: `project.md`)
 - Accessibility: WCAG 2.1 AA compliance (Reference: `project.md`)
 - SEO: Metadata, structured data (Reference: `project.md`)
-- Design System: Project design system usage (Reference: project's design system docs)
+- UI/UX Design: Visual hierarchy, UX laws, interaction patterns (Reference: `ui-ux-designer.json`)
 
 **Risk Assessment:**
 
@@ -499,7 +499,7 @@ All agent files are located directly in `.ai-rules/agents/` directory without su
 ├── devops-engineer.json             # Utility agent
 ├── accessibility-specialist.json    # Domain specialist
 ├── architecture-specialist.json     # Domain specialist
-├── design-system-specialist.json    # Domain specialist
+├── ui-ux-designer.json              # Domain specialist
 ├── documentation-specialist.json    # Domain specialist
 ├── performance-specialist.json      # Domain specialist
 ├── security-specialist.json         # Domain specialist

.ai-rules/agents/code-reviewer.json

@@ -98,7 +98,7 @@
       "🔴 Security: XSS/CSRF, authentication/authorization, input validation - Reference: project.md and .ai-rules/agents/security-specialist.json modes.evaluation framework for comprehensive security assessment",
       "🔴 Accessibility: WCAG 2.1 AA compliance - Reference: project.md 'UX & Accessibility' section and .ai-rules/agents/accessibility-specialist.json modes.evaluation framework for comprehensive accessibility assessment",
       "🔴 SEO: Metadata, structured data - Reference: project.md and .ai-rules/agents/seo-specialist.json modes.evaluation framework for comprehensive SEO assessment",
-      "🔴 Design System: Project design system usage - Reference: project.md 'Tech Stack' section, the project's design system documentation and .ai-rules/agents/design-system-specialist.json modes.evaluation framework for comprehensive design system assessment",
+      "🔴 UI/UX Design: Visual hierarchy, UX laws, interaction patterns - Reference: .ai-rules/agents/ui-ux-designer.json modes.evaluation framework for comprehensive UI/UX design assessment",
       "🔴 Documentation Quality: Documentation, cursor rules, and AI prompt quality - Reference: .ai-rules/agents/documentation-specialist.json modes.evaluation framework for clarity, completeness, consistency, actionability, structure, and references assessment",
       "Design Patterns: Latest React/Next.js patterns - See project.md 'Tech Stack' section for versions and .ai-rules/agents/code-quality-specialist.json for design pattern assessment"
     ],
@@ -110,7 +110,7 @@
       "test_quality": "When evaluating tests, reference Test Strategy Specialist Agent framework (`.ai-rules/agents/test-strategy-specialist.json`) modes.evaluation for test coverage, TDD workflow, and test quality assessment",
       "performance": "When evaluating performance, reference Performance Specialist Agent framework (`.ai-rules/agents/performance-specialist.json`) for bundle size, rendering optimization, and Core Web Vitals assessment",
       "seo": "When evaluating SEO, reference SEO Specialist Agent framework (`.ai-rules/agents/seo-specialist.json`) for metadata, structured data, and search engine optimization assessment",
-      "design_system": "When evaluating design system usage, reference Design System Specialist Agent framework (`.ai-rules/agents/design-system-specialist.json`) for design system usage, twJoin/twMerge, and design tokens assessment",
+      "ui_ux_design": "When evaluating UI/UX design, reference UI/UX Designer Agent framework (`.ai-rules/agents/ui-ux-designer.json`) for visual hierarchy, UX laws, and interaction patterns assessment",
       "documentation_quality": "When evaluating documentation, cursor rules, or AI prompts, reference Documentation Specialist Agent framework (`.ai-rules/agents/documentation-specialist.json`) modes.evaluation for clarity, completeness, consistency, actionability, structure, and references assessment"
     },