docs(ux): align user validation outcomes and PM scope
docs(ux): distinguish Site file and output guidance
docs(ux): record backup guidance and invalid file recovery
research: verify untitled creation and rename identity
research: connect UX evidence to shared UI decisions
research: verify body search and filter recovery
research: track failed document target across retry
research: observe reference and independent Site copy behavior
research: compare product workspace return paths
research: record product library focus return gap
docs: record library trash-state mismatch and issue 314
docs: compare product save guidance and preserve Note exception
docs: add UX research scope and local save observation