feat(ui): modularisation du css et fidélisation des composants à la maquette figma

- découpage du css par composant (navbar, hero, footer, global)
- ajustement pixel-perfect du footer (newsletter full-bleed, alignements, typographies)
- documentation et commentaires détaillés du code react et css

assets/app.js

@@ -1,10 +1,10 @@
-import './stimulus_bootstrap.js';
-/*
- * Welcome to your app's main JavaScript file!
- *
- * This file will be included onto the page via the importmap() Twig function,
- * which should already be in your base.html.twig.
- */
 import './styles/app.css';
+import React from 'react';
+import { createRoot } from 'react-dom/client';
+import Home from './components/Home.jsx'; // <-- Ajoute .jsx ici !
 
-console.log('This log comes from assets/app.js - welcome to AssetMapper! 🎉');
+const container = document.getElementById('root');
+if (container) {
+    const root = createRoot(container);
+    root.render(<Home />);
+}