Three coordinated guards close the orphan-creation paths:
- CreateChildAsync refuses when the parent is not in a planning phase.
- DiscardPlanningAsync now returns a structured DiscardPlanningOutcome
and refuses when children are queued or running; callers can opt into
auto-dequeuing queued kids via dequeueQueuedChildren=true. Terminal
children (Done/Failed/Cancelled) are promoted to top-level instead of
becoming orphans when the parent's PlanningPhase is reset.
- OrphanRecovery hosted service clears ParentTaskId on any rows whose
parent is missing or no longer in a planning phase on worker startup,
mirroring the StaleTaskRecovery pattern.
UI surfaces the block reason: a confirm dialog offers to dequeue queued
children and retry; a running-children block is shown as a hard error
asking the user to cancel first.
WorkerClient now negotiates the JsonStringEnumConverter so the
DiscardPlanningResult enum round-trips correctly over SignalR.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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