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/stimulus_bootstrap.js

@@ -0,0 +1,10 @@
+import { startStimulusApp } from '@symfony/stimulus-bridge';
+
+// Registers Stimulus controllers from controllers.json and in the controllers/ directory
+export const app = startStimulusApp(require.context(
+    '@symfony/stimulus-bridge/lazy-controller-loader!./controllers',
+    true,
+    /\.[jt]sx?$/
+));
+// register any custom, 3rd party controllers here
+// app.register('some_controller_name', SomeImportedController);