Running the mutants exposed two toothless guards before review did:
- reverting the keys to toFixed(6) no longer produced false П4 refusals
because the new 2e-7 incidence absorbed the debris pair — the REAL harm of
coarse keys is the opposite direction: nodes 4e-7 apart merged into one
key and П4 went blind to a genuine near-miss. AC1 now pins that case.
- the `break` patch failed to reproduce the old first-branch-only loss (the
frontier re-visits the node through the pushed endpoints); the patch now
truncates the node's candidate list to one entry, which loses forks the
way `.find` did — both the fork unit and the 10 000-atom run turn red.
Issue: #331
User-Visible: no