The legacy parser returns prepend + text + append, so its answer is refused
when a PromptManager-family node has a prepend or append part (#343). Junk
found at the undecided-graph step keeps that step's unlinked status and
review, so an ambiguous file is still queued for Needs review. The monitor
policy's ambiguous file no longer asks for the recorded run, and the file
size may be read lazily.