Function computeMarkerPositions

computeMarkerPositions(
    topics: BCFTopic[],
    boundsLookup: EntityBoundsLookup,
    options?: ComputeMarkersOptions,
): BCFMarker3D[]
Compute positioned 3D markers from BCF topics.

This is a pure function — no DOM, no renderer dependency. It takes a lookup callback so any renderer can provide entity bounds.
Parameters
- topics: BCFTopic[]
  Array of BCF topics to create markers for
- boundsLookup: EntityBoundsLookup
  Callback to resolve IFC GlobalId → bounding box (Y-up)
- Optionaloptions: ComputeMarkersOptions
  Optional configuration
Returns BCFMarker3D[]
Array of positioned markers (topics without derivable positions are skipped)