Function leading_rooted_global_id 

pub fn leading_rooted_global_id(line: &[u8]) -> Option<String>

The leading GlobalId of a raw STEP entity line, classified by TYPE (not just the 22-char shape): reads the type from the line and applies the rooted-entity rule, so a non-rooted entity leading with a 22-char charset Name (e.g. an IfcColourRgb) is not counted as a rooted GlobalId. For callers that only have raw text — the merge harness and duplicate-GlobalId diagnostics — and want the same classification the merge itself uses.