Cheap change detection for navigation loops. SHA-256 over per-node
fingerprints (className + text + contentDescription + bounds +
viewIdResourceName) across the full multi-window accessibility
tree. diff_screen reports changed + new hash + node_count in one
call so the agent can update its reference without an extra
round-trip. ~100x cheaper than re-reading the full tree for
'did anything change?' polling.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
