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>

scripts/hooks/gateguard-fact-force.js

@@ -84,7 +84,6 @@ function markChecked(key) {
 
 function isChecked(key) {
   const state = loadState();
-  saveState(state);
   return state.checked.includes(key);
 }