The gate hard-cloned `--branch ${patch_branch}`, so when that branch does not
exist it failed with "Remote branch ... not found in upstream origin". With
cascade detection live the proposer often has no candidates and never
(re)creates the branch, so "branch absent" is the normal "nothing to verify"
state, not an error.
Clone main, then fetch+checkout the patch branch only if it exists; otherwise
log and exit 0. A present branch is verified as before.
pat-s
47c436f2ed