chore(frontend): upgrade eslint and update config to new default config format

frontend/.eslintrc.json

@@ -1,17 +0,0 @@
-{
-  "extends": [
-    "next",
-    "eslint-config-next",
-    "eslint:recommended",
-    "prettier"
-  ],
-  "plugins": ["react"],
-  "rules": {
-    "quotes": ["warn", "double", { "allowTemplateLiterals": true }],
-    "react-hooks/exhaustive-deps": ["off"],
-    "import/no-anonymous-default-export": ["off"],
-    "no-unused-vars": ["warn"],
-    "react/no-unescaped-entities": ["off"],
-    "@next/next/no-img-element": ["off"]
-  }
-}

frontend/eslint.config.mjs

@@ -0,0 +1,34 @@
+import { defineConfig } from "eslint/config";
+import react from "eslint-plugin-react";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+import js from "@eslint/js";
+import { FlatCompat } from "@eslint/eslintrc";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+const compat = new FlatCompat({
+    baseDirectory: __dirname,
+    recommendedConfig: js.configs.recommended,
+    allConfig: js.configs.all
+});
+
+export default defineConfig([{
+    extends: compat.extends("next", "eslint-config-next", "eslint:recommended", "prettier"),
+
+    plugins: {
+        react,
+    },
+
+    rules: {
+        quotes: ["warn", "double", {
+            allowTemplateLiterals: true,
+        }],
+
+        "react-hooks/exhaustive-deps": ["off"],
+        "import/no-anonymous-default-export": ["off"],
+        "no-unused-vars": ["warn"],
+        "react/no-unescaped-entities": ["off"],
+        "@next/next/no-img-element": ["off"],
+    },
+}]);

frontend/package.json

@@ -44,9 +44,10 @@
     "@types/react-dom": "18.3.0",
     "@typescript-eslint/parser": "^8.6.0",
     "axios": "^1.7.7",
-    "eslint": "8.57.0",
-    "eslint-config-next": "^14.2.12",
-    "eslint-config-prettier": "^9.1.0",
+    "eslint": "9.23.0",
+    "eslint-config-next": "^15.2.4",
+    "eslint-config-prettier": "^10.1.1",
+    "eslint-plugin-react": "^7.37.4",
     "prettier": "^3.3.3",
     "tar": "^7.4.3",
     "typescript": "^5.6.2"