chore(backend): update package-lock and upgrade eslint with config to new default config format

backend/eslint.config.mjs

@@ -0,0 +1,27 @@
+import { defineConfig } from "eslint/config";
+import typescriptEslint from "@typescript-eslint/eslint-plugin";
+import tsParser from "@typescript-eslint/parser";
+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("eslint:recommended", "plugin:@typescript-eslint/recommended"),
+
+    plugins: {
+        "@typescript-eslint": typescriptEslint,
+    },
+
+    languageOptions: {
+        parser: tsParser,
+    },
+}]);