feat(ui): enhance UI with animations, dark mode support and and improved components

- Add framer-motion page transitions and AnimatePresence support
- Add dark mode support across all components
- Create reusable UI components (Button, Badge, Card, EmptyState, Input, Toast, Skeleton)
- Add CSS custom properties for consistent theming
- Add animation variants and utility functions
- Improve ChatArea, Sidebar, TriggersPanel with animations

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

desktop/src/components/TriggersPanel.tsx

@@ -15,8 +15,6 @@ import {
   Globe,
   Bell,
   MessageSquare,
-  AlertCircle,
-  CheckCircle2,
   X,
 } from 'lucide-react';