chore: strict unused check (#3215)

Author: dai-shi

eslint.config.mjs

@@ -67,7 +67,7 @@ export default tseslint.config(
       ],
       '@typescript-eslint/no-explicit-any': 'off',
       '@typescript-eslint/no-unused-vars': [
-        'warn',
+        'error',
         { argsIgnorePattern: '^_', varsIgnorePattern: '^_' },
       ],
       'react-hooks/react-compiler': 'error',
@@ -80,7 +80,6 @@ export default tseslint.config(
     ...vitest.configs.recommended,
     rules: {
       'import/extensions': ['error', 'never'],
-      '@typescript-eslint/no-unused-vars': 'off',
       'testing-library/no-node-access': 'off',
       'vitest/consistent-test-it': [
         'error',