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/src/state/index.ts

@@ -0,0 +1,22 @@
+// DSS Admin UI - State Management with Preact Signals
+// Central export for all state
+
+export * from './app';
+export * from './project';
+export * from './team';
+export * from './user';
+
+import { loadProjects } from './project';
+import { loadUserPreferences } from './user';
+
+/**
+ * Initialize the application state
+ * Called once on app mount
+ */
+export async function initializeApp(): Promise<void> {
+  // Load user preferences from localStorage
+  loadUserPreferences();
+
+  // Load projects from API
+  await loadProjects();
+}