pub fn semantic_occurrence_fingerprint(
content: FragmentFingerprint,
host: &UnitFingerprint,
occurrence_rank: u32,
) -> FragmentFingerprintExpand description
Identify one semantic fragment occurrence inside its stable host unit.
Semantic content intentionally excludes source position, so identical windows in distinct hosts need this separate identity before they can form a group without collapsing. The rank is assigned once per host by the scan after deterministic window extraction; it is not a source offset.