## Summary
- Fixes a regression from #21176 where activating a workflow caused it
to disappear until page refresh
- Root cause: when a draft is activated (status DRAFT→ACTIVE),
`useEffectiveDraftVersionId` incorrectly treated it as a discard because
the cached version was no longer DRAFT, filtering it from the versions
list
- Fix: only set `lastDiscardedDraftId` when `deletedAt` is actually set
on the cached version, not when the status simply changes
## Test plan
- [x] Open a workflow with a DRAFT version
- [x] Activate the workflow → verify it does NOT disappear
- [x] Discard a draft → verify header does NOT flicker between
DRAFT/ACTIVE
Thomas Trompette
4e1cc2d831