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.

.gitignore

@@ -0,0 +1,5 @@
+node_modules
+dist
+.env
+.DS_Store
+.tanstack