A committed update exits 0 and prints one whole "Update follow-up '<step>'
did not finish:" line per owed step (update_receipt.record_followup). The
hand-offs only reacted to the Desktop build line, so a gateway proven to
run old code (gateway_restart), a refused Windows resume, a lost
completion or a failed channel adoption ended as a plain
"Update complete.".
posix.sh collects the distinct owed steps from that line
(owed_followup_steps) and turns them into the manual result message
(DONE_NOTE, the only channel the main-based script has); a gateway_restart
adds the `hermes gateway restart` hint. windows.ps1 does the same through
its manual outcome. With #132354's add_warning protocol the same
owed_followup_steps output feeds one add_warning per step.
record_followup's docstring names the line as a protocol; a contract test
runs the real posix.sh parser and the windows.ps1 regex against it.
Review: kshitijk4poor 5411222454 regression 1 / open thread F6.
260cef995a