optionalGroupIdSet falls back to builtin:coding (mirroring the executor's
unselected-task resolution) so a toggled built-in group id like
browser-verification is no longer downgraded to a legacy WS-xxx step row the
graph executor never matches. Create-time optional-step controls resolve
builtin:coding when no project default workflow is set so the toggles render.
First unit of the graph-native workflow-step refactor (see
docs/plans/2026-06-25-001-refactor-workflow-steps-graph-native-plan.md).
Fusion-Task-Id: FN-7039
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>