Function load_props_for 

pub async fn load_props_for(
    drawing: &Drawing,
    conn: &mut AsyncPgConnection,
) -> QueryResult<DrawingVariantEntity>

Load properties for a specific drawing.

This inspects drawing.shape_type and loads the corresponding props row(s) from the correct props table.

For FreeLine and BezierPolygon, this additionally:

• Loads the ordered list of all point rows
• Returns an aggregated DrawingVariantEntity containing both props and points

Errors

• If the props row for the drawing does not exist
• If point rows fail to load or violate ordering assumptions