Macro library_type_matches_item 

macro_rules! library_type_matches_item {
    () => { ... };
}

The Jellyfin taxonomy half of “does cached item i belong to library l”: the library’s collection_type against the item’s item_type.

A macro rather than a const because both callers need it inside a larger SQL string literal, and concat! cannot take a const. One definition, so the two sites cannot drift — they did once already, and opening any downloaded library then listed every downloaded item on the server (DR-167).

Deliberately has no fall-open arm. Adding “…or the type is unknown” makes the clause true for every row, which is precisely the defect it exists to prevent; callers that want that behaviour must say so themselves and justify it, as LIBRARY_HOLDS_ITEM does.

TRACES: UR-007, UR-055 | DR-167, DR-277