Committing work found uncommitted in the checkout: --base lets a unit be based
on a branch other than main (used throughout the M32 cut-over session for
u6-tests and hatchmate-migration bases), and the bare 'return' statements
become 'return 0' so they cannot abort under set -e when the preceding test is
false.
Per the project agent-safety rule: untracked/uncommitted work that matters gets
committed the day it is found, so local loss cannot take it.
Claude-Session: https://claude.ai/code/session_014KNyfHmHpMbdMrHZXDRkAp
cbab812917