feat: initialize React app with TanStack Router and Vitest for testing

- Added App component with basic structure and styling.
- Included CSS for app layout and animations.
- Integrated TanStack Router for routing management.
- Set up Vitest for testing with a basic test case for the App component.
- Added logo SVG for branding.
- Configured Vite for development with React and TanStack Devtools.
- Created reportWebVitals utility for performance measurement.
- Established global styles in styles.css.

my-app/.gitignore

@@ -0,0 +1,10 @@
+node_modules
+.DS_Store
+dist
+dist-ssr
+*.local
+count.txt
+.env
+.nitro
+.tanstack
+.wrangler