feat: add CodeMirror-based code editor component and routing setup

- Implemented CodeEditor component using CodeMirror for JavaScript editing.
- Added global styles in index.css for consistent UI.
- Set up routing with TanStack Router, including root and nested routes.
- Created About, C, and Editor routes with respective components.
- Integrated CodeEditor into the Editor route for code editing functionality.
- Configured TypeScript settings in tsconfig.json for strict type checking.
- Established Vite configuration for React and TanStack Router integration.

vite.config.ts

@@ -0,0 +1,17 @@
+// vite.config.ts
+import { defineConfig } from 'vite'
+import react from '@vitejs/plugin-react'
+import { tanstackRouter } from '@tanstack/router-plugin/vite'
+
+// https://vitejs.dev/config/
+export default defineConfig({
+  plugins: [
+    // Please make sure that '@tanstack/router-plugin' is passed before '@vitejs/plugin-react'
+    tanstackRouter({
+      target: 'react',
+      autoCodeSplitting: true,
+    }),
+    react(),
+    // ...
+  ],
+})