chore(deps): upgrade eslint to v9

eslint.config.mjs

@@ -0,0 +1,65 @@
+import tsEslintPlugin from '@typescript-eslint/eslint-plugin';
+import globals from 'globals';
+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 [
+  ...compat.extends(
+    'plugin:@typescript-eslint/recommended',
+    'plugin:prettier/recommended',
+  ),
+  {
+    plugins: {
+      '@typescript-eslint': tsEslintPlugin,
+    },
+    languageOptions: {
+      globals: {
+        ...globals.node,
+        ...globals.jest,
+      },
+      parser: tsParser,
+      ecmaVersion: 5,
+      sourceType: 'module',
+      parserOptions: {
+        project: 'tsconfig.json',
+        tsconfigRootDir: __dirname,
+      },
+    },
+    rules: {
+      '@typescript-eslint/interface-name-prefix': 'off',
+      '@typescript-eslint/explicit-function-return-type': 'off',
+      '@typescript-eslint/explicit-module-boundary-types': 'off',
+      '@typescript-eslint/no-explicit-any': 'off',
+      'no-unused-vars': 'off',
+      '@typescript-eslint/no-unused-vars': ['error'],
+      'require-await': 'off',
+      '@typescript-eslint/require-await': 'error',
+      '@typescript-eslint/no-floating-promises': 'error',
+      'no-restricted-syntax': [
+        'error',
+        {
+          selector:
+            'CallExpression[callee.object.name=configService][callee.property.name=/^(get|getOrThrow)$/]:not(:has([arguments.1] Property[key.name=infer][value.value=true])), CallExpression[callee.object.property.name=configService][callee.property.name=/^(get|getOrThrow)$/]:not(:has([arguments.1] Property[key.name=infer][value.value=true]))',
+          message:
+            'Add "{ infer: true }" to configService.get() for correct typechecking. Example: configService.get("database.port", { infer: true })',
+        },
+        {
+          selector:
+            'CallExpression[callee.name=it][arguments.0.value!=/^should/]',
+          message: '"it" should start with "should"',
+        },
+      ],
+    },
+  },
+];