feat: initialize project with Symfony, React, and Tailwind CSS setup

- Add package.json with development and production dependencies
- Create postcss.config.js for Tailwind CSS integration
- Implement AdminController for handling admin routes
- Add admin index template with React root element
- Create base template for consistent layout
- Configure TypeScript with tsconfig.json
- Set up Webpack configuration for asset management

assets/controllers.json

@@ -0,0 +1,11 @@
+{
+    "controllers": {
+        "@symfony/ux-react": {
+            "react": {
+                "enabled": true,
+                "fetch": "eager"
+            }
+        }
+    },
+    "entrypoints": []
+}