Genuine content conflict: the surfaces the Architect declared disjoint were not.
Uncommitted tracked changes stopped the rebase before it compared anything.
The run branch kept moving under us; nothing is wrong with the work.
Missing ref, unreadable head, git invocation failure.
Why a fold did not land (#223). The old shape was a single
conflictboolean, which made "overlapping file-contact surfaces, a plan defect" the diagnosis for every way a rebase can fail — including ones the architecture rules out. Onlyconflictis a plan defect, and only a plan defect is fatal.