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

package.json

@@ -0,0 +1,29 @@
+{
+    "name": "gaea21-v2-web",
+    "type": "module",
+    "private": true,
+    "license": "UNLICENSED",
+    "scripts": {
+        "dev-server": "encore dev-server",
+        "dev": "encore dev",
+        "watch": "encore dev --watch",
+        "build": "encore production --progress"
+    },
+    "devDependencies": {
+        "@babel/core": "^7.24.0",
+        "@babel/preset-env": "^7.24.0",
+        "@babel/preset-react": "^7.24.0",
+        "@symfony/webpack-encore": "^5.1.0",
+        "autoprefixer": "^10.6.1",
+        "babel-plugin-polyfill-corejs3": "^1.0.0",
+        "core-js": "^3.40.0",
+        "postcss-loader": "^8.1.0",
+        "tailwindcss": "^3.4.0",
+        "webpack": "^5.90.0",
+        "webpack-cli": "^5.1.4"
+    },
+    "dependencies": {
+        "react": "^18.3.1",
+        "react-dom": "^18.3.1"
+    }
+}