Add backend policy tests and API client split

backend/package.json

@@ -3,15 +3,18 @@
   "version": "1.0.0",
   "type": "commonjs",
   "main": "index.js",
+  "scripts": {
+    "test": "node --test"
+  },
   "dependencies": {
     "bcryptjs": "^3.0.3",
     "cors": "^2.8.5",
     "dotenv": "^16.4.7",
     "express": "^4.18.2",
     "jsonwebtoken": "^9.0.3",
-    "multer": "^1.4.5-lts.1",
+    "multer": "^2.1.0",
     "mysql2": "^3.9.1",
     "nodemailer": "^8.0.1",
-    "uuid": "^9.0.1"
+    "uuid": "^13.0.0"
   }
 }