add linting and some lazy loading

frontend/package.json

@@ -40,8 +40,10 @@
     "workbox-streams": "^7.1.0"
   },
   "devDependencies": {
+    "@typescript-eslint/parser": "^8.31.1",
     "@vitejs/plugin-react": "^4.3.4",
     "@types/downloadjs": "^1.4.4",
+    "eslint": "^9.24.0",
     "jsdom": "^25.0.1",
     "less": "^4.2.0",
     "vite": "^5.4.10",
@@ -51,6 +53,7 @@
     "dev": "vite",
     "start": "vite",
     "build": "vite build",
+    "lint": "eslint \"src/**/*.{ts,tsx}\" vite.config.ts vitest.setup.ts",
     "preview": "vite preview",
     "test": "vitest run",
     "test:watch": "vitest"