preview_has_truncation_marker: bool = FalseWhether the preview contains a ... [N lines truncated] ... marker.
Set by the code that builds the preview. This is the only reliable way to know the marker was inserted, as the command output itself can contain a line that looks the same (scanning the text is unsafe).
This flag covers only the ... [N lines truncated] ... marker. A preview
may disclose other losses through its own in-band clip notices, which need
no flag because they carry their own explanation; see
_build_capture_execute_cmd in backends.sandbox for the wording.
When offloaded is False, this flag is always False.