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/vite.config.js

@@ -0,0 +1,14 @@
+import { defineConfig } from 'vite'
+import { devtools } from '@tanstack/devtools-vite'
+import viteReact from '@vitejs/plugin-react'
+import { fileURLToPath, URL } from 'node:url'
+
+// https://vitejs.dev/config/
+export default defineConfig({
+  plugins: [devtools(), viteReact()],
+  resolve: {
+    alias: {
+      '@': fileURLToPath(new URL('./src', import.meta.url)),
+    },
+  },
+})