`_check_execution_error` only emitted `AgentExecutionErrorEvent` once the
retries were exhausted, but each retry re-enters `execute_task` and opens a
new `agent_execution_started` scope. The scopes left open were then popped
by the next ending event, so `task_failed` closed an agent scope instead of
`task_started` and the task never got its own terminal pairing. Passthrough
exceptions keep bubbling untouched, since a HITL pause must leave its scope
open for the resume.
1ad1032f9d