src/merge.rs, pure: every network sink more than the merge depth ahead and none of our blocks in the network's view for 120 s. Engine polls the observer's view every 30 s while mining and runs the check after sync_decision_v2; state behind, sync_cause not merging, one error event. Known-failed test first; 172 box tests, 42 UI tests.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>