feat(sync): use on-disk content hashing to skip unchanged sync work

eslint.config.js

@@ -13,6 +13,14 @@ export default [
     rules: {
       // Toolkit `recommended` prefers `interface`; this project prefers `type`.
       '@typescript-eslint/consistent-type-definitions': ['error', 'type'],
+      '@typescript-eslint/no-unused-vars': [
+        'error',
+        {
+          argsIgnorePattern: '^_',
+          varsIgnorePattern: '^_',
+          caughtErrorsIgnorePattern: '^_',
+        },
+      ],
     },
   },
   {