refactor(frontend): lint, one session guard, one request helper, one user context

package.json

@@ -7,7 +7,8 @@
     "dev": "vite",
     "build": "vite build",
     "preview": "vite preview",
-    "test": "vitest run"
+    "test": "vitest run",
+    "lint": "eslint ."
   },
   "dependencies": {
     "@fontsource-variable/inter": "^5.3.0",
@@ -29,10 +30,14 @@
     "zod": "^3.25.76"
   },
   "devDependencies": {
+    "@eslint/js": "^10.0.1",
     "@testing-library/dom": "^10.4.2",
     "@testing-library/react": "^16.3.3",
     "@vitejs/plugin-react": "^6.1.1",
     "autoprefixer": "~10.6.1",
+    "eslint": "^10.11.0",
+    "eslint-plugin-react-hooks": "^7.1.1",
+    "globals": "^17.12.0",
     "jsdom": "^30.1.1",
     "postcss": "~8.5.28",
     "tailwindcss": "~4.3.3",