When the debugger pauses after job completion, surface the synthetic
"Complete job" entry as the active stack frame so clients highlight
the cleanup line. Previously the position stayed on the last real step.
Threads CompleteJobLine through RenderResult / JobExecutionView and
gates HandleStackTrace on a new _jobCompleted flag set when
OnJobCompletedAsync enters its inspection pause.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>