feat: Rebuild admin-ui with Preact + Signals

Complete rebuild of the admin-ui using Preact + Signals for a lightweight,
reactive framework. Features include:

- Team-centric workdesks (UI, UX, QA, Admin)
- Comprehensive API client with 150+ DSS backend endpoints
- Dark mode with system preference detection
- Keyboard shortcuts and command palette
- AI chat sidebar with Claude integration
- Toast notifications system
- Export/import functionality for project backup
- TypeScript throughout with full type coverage

Bundle size: ~66KB main (21KB gzipped), ~5KB framework overhead

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

admin-ui/package.json

@@ -1,30 +1,30 @@
 {
   "name": "dss-admin-ui",
-  "version": "1.0.0",
-  "description": "DSS Admin UI - Configuration and Component Management",
+  "version": "2.0.0",
+  "description": "DSS Admin UI - Design System Server Management",
   "private": true,
   "type": "module",
   "scripts": {
     "dev": "vite",
+    "build": "tsc && vite build",
     "preview": "vite preview",
-    "build": "vite build",
     "test": "vitest",
     "test:watch": "vitest --watch",
     "test:ui": "vitest --ui",
-    "test:coverage": "vitest --coverage",
-    "test:debug": "vitest --inspect-brk --inspect-port=9229 --no-coverage"
+    "test:coverage": "vitest --coverage"
+  },
+  "dependencies": {
+    "preact": "^10.19.0",
+    "@preact/signals": "^1.2.0"
   },
   "devDependencies": {
-    "@testing-library/dom": "^9.3.0",
-    "@testing-library/jest-dom": "^6.1.0",
-    "@vitejs/plugin-basic-ssl": "^1.0.0",
-    "@vitest/ui": "^1.0.0",
-    "jsdom": "^22.1.0",
-    "terser": "^5.44.1",
+    "@preact/preset-vite": "^2.8.0",
+    "@testing-library/preact": "^3.2.0",
+    "@types/node": "^20.10.0",
+    "typescript": "^5.3.0",
     "vite": "^5.0.0",
-    "vitest": "^1.0.0"
-  },
-  "vitest": {
-    "globals": true
+    "vite-plugin-pwa": "^0.17.0",
+    "vitest": "^1.0.0",
+    "workbox-window": "^7.0.0"
   }
 }