feat: Story 9 - Remove scroll bars for cleaner UI

Implemented Story 9: Hidden Scroll Bars
- Added CSS to hide scroll bars globally while maintaining functionality
- Used scrollbar-width: none for Firefox
- Used ::-webkit-scrollbar { display: none; } for Chrome/Safari/Edge
- Set overflow-x: hidden to prevent unwanted horizontal scrolling
- Maintained full scroll functionality (mouse wheel, trackpad, keyboard)

Updated Specs
- Added Scroll Bar Styling section to UI_UX.md
- Documented cross-browser compatibility requirements
- Specified areas affected and implementation approach

Bug Fixes
- Fixed biome linting issues in App.tsx (import organization, button type)
- Applied biome formatter for consistent code style

package.json

@@ -7,7 +7,8 @@
     "dev": "vite",
     "build": "tsc && vite build",
     "preview": "vite preview",
-    "tauri": "tauri"
+    "tauri": "tauri",
+    "test": "jest"
   },
   "dependencies": {
     "@tauri-apps/api": "^2",
@@ -24,6 +25,11 @@
     "@types/react-dom": "^19.1.6",
     "@vitejs/plugin-react": "^4.6.0",
     "typescript": "~5.8.3",
-    "vite": "^7.0.4"
+    "vite": "^7.0.4",
+    "jest": "^29.0.0",
+    "ts-jest": "^29.0.0",
+    "@testing-library/react": "^14.0.0",
+    "@testing-library/jest-dom": "^6.0.0",
+    "@testing-library/user-event": "^14.4.3"
   }
 }