Function export_hbjson 

pub fn export_hbjson(content: &[u8], opts: &HbjsonOptions) -> String

Export the IfcSpace volumes in content (raw IFC/STEP bytes) as an HBJSON string.

Rooms are built analytically from extruded-area profiles (watertight by construction); faces are typed Floor / RoofCeiling / Wall with outward normals. Returns a Honeybee-valid Model JSON ready to load via honeybee.model.Model.from_hbjson.