refactor: move backend in apps/backend

apps/backend/package.json

@@ -0,0 +1,19 @@
+{
+    "$schema": "https://json.schemastore.org/package.json",
+    "private": true,
+    "type": "module",
+    "scripts": {
+        "build": "vite build",
+        "dev": "vite --port 5174"
+    },
+    "devDependencies": {
+        "@tailwindcss/vite": "^4.0.0",
+        "axios": "^1.11.0",
+        "concurrently": "^9.0.1",
+        "laravel-echo": "^2.2.7",
+        "laravel-vite-plugin": "^2.0.0",
+        "pusher-js": "^8.4.0",
+        "tailwindcss": "^4.0.0",
+        "vite": "^7.0.7"
+    }
+}