Gate item labels restart at every gate revision, but decision rows were minted
as <run>-<label>, so a second gate reused the first gate's ids and
gstack-artifact validate failed the export (ARTIFACT_DUPLICATE_ID). Revisions
after the first mint <run>-r<rev>-<label> through one decisionId helper, and
exported tasks block on the current gate's plan approval.
Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>