feat: refactor user handling and integrate toast notifications for login feedback

frontend_admin/package-lock.json

@@ -16,6 +16,7 @@
         "lucide-react": "^0.525.0",
         "react": "^19.1.0",
         "react-dom": "^19.1.0",
+        "react-toastify": "^11.0.5",
         "tailwind-merge": "^3.3.1",
         "tailwindcss-animate": "^1.0.7",
         "tw-animate-css": "^1.3.5"
@@ -4010,6 +4011,19 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/react-toastify": {
+      "version": "11.0.5",
+      "resolved": "https://registry.npmjs.org/react-toastify/-/react-toastify-11.0.5.tgz",
+      "integrity": "sha512-EpqHBGvnSTtHYhCPLxML05NLY2ZX0JURbAdNYa6BUkk+amz4wbKBQvoKQAB0ardvSarUBuY4Q4s1sluAzZwkmA==",
+      "license": "MIT",
+      "dependencies": {
+        "clsx": "^2.1.1"
+      },
+      "peerDependencies": {
+        "react": "^18 || ^19",
+        "react-dom": "^18 || ^19"
+      }
+    },
     "node_modules/resolve-from": {
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/resolve-from/-/resolve-from-4.0.0.tgz",