Add reusable UI components and update dependencies

Introduce new `Toaster`, `Tabs`, `DropdownMenu`, and `Table` components under `ui` for consistent design and functionality. Updated `next-themes` to `^0.4.6` and added `sonner` as a notification library to support the `Toaster` component.

frontend/package-lock.json

@@ -29,9 +29,10 @@
         "jwt-decode": "^4.0.0",
         "lucide-react": "^0.477.0",
         "next": "15.2.0",
-        "next-themes": "^0.4.4",
+        "next-themes": "^0.4.6",
         "react": "^19.0.0",
         "react-dom": "^19.0.0",
+        "sonner": "^2.0.1",
         "tailwind-merge": "^3.0.2",
         "tailwindcss-animate": "^1.0.7"
       },
@@ -5676,9 +5677,9 @@
       }
     },
     "node_modules/next-themes": {
-      "version": "0.4.4",
-      "resolved": "https://registry.npmjs.org/next-themes/-/next-themes-0.4.4.tgz",
-      "integrity": "sha512-LDQ2qIOJF0VnuVrrMSMLrWGjRMkq+0mpgl6e0juCLqdJ+oo8Q84JRWT6Wh11VDQKkMMe+dVzDKLWs5n87T+PkQ==",
+      "version": "0.4.6",
+      "resolved": "https://registry.npmjs.org/next-themes/-/next-themes-0.4.6.tgz",
+      "integrity": "sha512-pZvgD5L0IEvX5/9GWyHMf3m8BKiVQwsCMHfoFosXtXBMnaS0ZnIJ9ST4b4NqLVKDEm8QBxoNNGNaBv2JNF6XNA==",
       "license": "MIT",
       "peerDependencies": {
         "react": "^16.8 || ^17 || ^18 || ^19 || ^19.0.0-rc",
@@ -6715,6 +6716,16 @@
         "is-arrayish": "^0.3.1"
       }
     },
+    "node_modules/sonner": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/sonner/-/sonner-2.0.1.tgz",
+      "integrity": "sha512-FRBphaehZ5tLdLcQ8g2WOIRE+Y7BCfWi5Zyd8bCvBjiW8TxxAyoWZIxS661Yz6TGPqFQ4VLzOF89WEYhfynSFQ==",
+      "license": "MIT",
+      "peerDependencies": {
+        "react": "^18.0.0 || ^19.0.0 || ^19.0.0-rc",
+        "react-dom": "^18.0.0 || ^19.0.0 || ^19.0.0-rc"
+      }
+    },
     "node_modules/source-map": {
       "version": "0.6.1",
       "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.6.1.tgz",