Extend the managed group stream with authoritative per-target terminal outcomes and structured failure classifications. Final client events are published first, followed by exactly one TargetFinished outcome for success, peer close, no-test, opening/runtime failure, removal, or cancellation.
Scheduler-owned cleanup now stops the receiver and seals subscriptions on natural completion, eliminating the event-consumer/join circular wait while preserving queued drain. TargetEventSubscription now yields ManagedGroupEvent, so consumers must handle Client and TargetFinished variants.
Strict-timeout regressions cover mixed success/failure, all-open failure, runtime failure, no-test ordering, removal, cancellation, and disconnection before join.
Nils Andreas Svee
97aac829ec