fix: remove unnecessary disk I/O + fix test cleanup

- isChecked() no longer calls saveState() — read-only operation
  should not write to disk (was causing 3x writes per tool call)
- Test cleanup uses fs.rmSync(recursive) instead of fs.rmdirSync
  which failed with ENOTEMPTY when .tmp files remained

9/9 tests pass.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/hooks/gateguard-fact-force.test.js

@@ -308,10 +308,9 @@ function runTests() {
   })) passed++; else failed++;
 
   // Cleanup: remove test-isolated state directory
-  clearState();
   try {
     if (fs.existsSync(stateDir)) {
-      fs.rmdirSync(stateDir);
+      fs.rmSync(stateDir, { recursive: true, force: true });
     }
   } catch (err) {
     console.error(`  [cleanup] failed to remove ${stateDir}: ${err.message}`);