chore(frontend): eslint flat config + prettier baseline config

frontend/package.json

@@ -8,7 +8,11 @@
     "dev": "vite",
     "build": "tsc --noEmit && vite build",
     "preview": "vite preview",
-    "check": "tsc --noEmit && vitest run && vite build"
+    "check": "tsc --noEmit && vitest run && vite build",
+    "lint": "eslint .",
+    "lint:fix": "eslint . --fix",
+    "format": "prettier --write .",
+    "format:check": "prettier --check ."
   },
   "keywords": [],
   "author": "",
@@ -32,12 +36,20 @@
     "tw-animate-css": "^1.4.0"
   },
   "devDependencies": {
+    "@eslint/js": "^10.0.1",
     "@tailwindcss/vite": "^4.3.3",
     "@types/react": "^19.2.18",
     "@types/react-dom": "^19.2.7",
+    "@typescript/native": "npm:typescript@^7.0.2",
     "@vitejs/plugin-react": "^6.1.1",
+    "eslint": "^10.10.0",
+    "eslint-config-prettier": "^10.1.8",
+    "eslint-plugin-jsx-a11y": "^6.10.2",
+    "eslint-plugin-react-hooks": "^7.1.1",
+    "prettier": "^3.9.6",
     "tailwindcss": "^4.3.3",
-    "typescript": "^7.0.2",
+    "typescript": "npm:@typescript/typescript6@^6.0.2",
+    "typescript-eslint": "^8.70.0",
     "vite": "^8.2.2",
     "vite-plugin-pwa": "^1.3.0",
     "vitest": "^5.0.0"