feat: add global styles and transitions for dark mode support

- Created style.css for base styles and color variables for light and dark themes.
- Added tailwind.css for Tailwind CSS integration and custom theme variables.
- Introduced transitions.css to manage global transitions and reduce motion preferences.
- Updated tsconfig.app.json to include path aliases for easier imports.
- Modified tsconfig.json to set baseUrl and paths for module resolution.
- Added typed-router.d.ts for auto-generated route types.
- Enhanced vite.config.ts with Vue Router plugin, Tailwind CSS integration, and server proxy settings.

frontend/styles/transitions.css

@@ -0,0 +1,9 @@
+/* Global transitions */
+
+/* Disable all transitions for users who prefer reduced motion */
+@media (prefers-reduced-motion: reduce) {
+  * {
+    transition: none !important;
+    animation: none !important;
+  }
+}