- Add Store.SavePlanWithRevision: single-transaction planning upsert +
revision bump (bump first with optimistic lock, conflict rolls back
before any plan write), closing the SaveWorkflowPlan split-transaction
race where plan content and revision could diverge
- AdvanceStage now takes operatorID and writes completed_by explicitly
instead of SELECT activated_by, so the completing operator is the
actual advancing user, not the original activator
- Service.SaveWorkflowPlan/AdvanceStage pass userID through; memStore
implements SavePlanWithRevision under its single mutex
Co-authored-by: Cursor <cursoragent@cursor.com>