Function compact_boundary_frame 

fn compact_boundary_frame(value: &Value) -> Value

The boundary row in the shape the wire sends.

A transcript spells its metadata flat and camelCase (compactMetadata, preTokens), while the decoder keys on the wire’s nesting - so a row handed on as read decodes as a generic system frame, and draws bare or half-filled where a live boundary draws its counts. The row’s own stamp rides with it: the frame is built here rather than copied, so this is where a page’s clock would lose the one fact only the file has.