refactor(adminfront): replace sonner with custom use-toast matching devfront UX policy

adminfront/package-lock.json

@@ -26,7 +26,6 @@
         "react-hook-form": "^7.71.1",
         "react-oidc-context": "^3.3.0",
         "react-router-dom": "^6.28.2",
-        "sonner": "^2.0.7",
         "tailwind-merge": "^3.4.0",
         "zod": "^3.24.1"
       },
@@ -5156,16 +5155,6 @@
       "dev": true,
       "license": "ISC"
     },
-    "node_modules/sonner": {
-      "version": "2.0.7",
-      "resolved": "https://registry.npmjs.org/sonner/-/sonner-2.0.7.tgz",
-      "integrity": "sha512-W6ZN4p58k8aDKA4XPcx2hpIQXBRAgyiWVkYhT7CvK6D3iAu7xjvVyhQHg2/iaKJZ1XVJ4r7XuwGL+WGEK37i9w==",
-      "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-js": {
       "version": "1.2.1",
       "resolved": "https://registry.npmjs.org/source-map-js/-/source-map-js-1.2.1.tgz",