TRUNCATION_MARKER_TEMPLATE: Final = '... [{omitted_lines} lines truncated] ...'Marker standing in for lines dropped from the middle of a head/tail preview.
Shared by _message_eviction._create_content_preview and the capture wrapper
in backends.sandbox so both emit identical marker text.
Never scan preview text for this marker to detect truncation: output can
contain a literal marker line. Producers report marker presence out of band
instead (see ExecuteOffloadResult.preview_has_truncation_marker).
Note: middleware.filesystem._LEGACY_TOO_LARGE_TOOL_MSG keeps a frozen copy of
the old wording for a deprecated import and deliberately does not use this
template.