Function read_schema_coherence_ranged 

pub fn read_schema_coherence_ranged<R: RangeReader>(
    reader: &R,
) -> Result<Option<Vec<Inconsistency>>, FileError>

Dictionary-free Tier-0 coherence read. Fetch only the header and the pyramid-meta range (2 small range reads) and run schema_coherence over the schema pyramid — never touching the dictionary (which a literal-heavy file makes large) or the triple index. Ok(None) if the file ships no pyramid.

This is what makes the Tier-0 check cheap on big graphs: the schema pyramid carries its own class-string table, so coherence needs none of the dictionary.