refactor: migrate from react-hot-toast to react-toastify and replace all emoji icons with Lucide React

- Replaced react-hot-toast with react-toastify (ToastContainer in providers.tsx)
- Removed @heroicons/react dependency
- Added lucide-react for consistent SVG icon system
- Migrated all 18 frontend pages from emoji icons to Lucide components
- Updated sidebar navigation, login/register, dashboard, apps, deploy,
  tickets, admin users/clusters/pools pages
- All emoji indicators (status, runtime, actions) now use proper SVG icons
- Build passes with zero TypeScript errors

frontend/package.json

@@ -9,15 +9,15 @@
     "lint": "next lint"
   },
   "dependencies": {
-    "@heroicons/react": "^2.1.0",
     "@tanstack/react-query": "^5.17.0",
     "axios": "^1.6.0",
     "clsx": "^2.1.0",
+    "lucide-react": "^1.7.0",
     "next": "14.1.0",
     "react": "^18.2.0",
     "react-dom": "^18.2.0",
     "react-hook-form": "^7.49.0",
-    "react-hot-toast": "^2.4.1",
+    "react-toastify": "^11.0.5",
     "zustand": "^4.5.0"
   },
   "devDependencies": {