When a home's gateway had never started (no last-known-good promotion record),
`doctor --fix` on an unparseable openclaw.json declined recovery and wrote a
stripped best-effort config — silently dropping the user's gateway/models
sections — then exited 0. Preserve the original as `.clobbered.*` and refuse to
apply repairs (exit 1 with the preserved path) when the config is unparseable
and unrecoverable. Shared preserveConfigSnapshotAsClobbered helper; the
promoted-recovery path is unchanged.