Point clouds: drawn from their scans, placed, cropped and attached as the reference does

Scans (.rcs) and projects (.rcp) are read and their points drawn as
screen-sized dots, coloured by the cloud's stylization. The cloud's
placement carries its scale and rotation; its extents and crops stay in
the scan's coordinates. A missing scan shows the extents with the saved
path. -POINTCLOUDATTACH / POINTCLOUDATTACH, POINTCLOUDCROP and the
POINTCLOUD* settings follow the reference's prompts and messages, the
Properties list is the reference's, and a locked cloud is left alone by
edits.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/scene/cache/properties.rs

@@ -105,11 +105,16 @@ pub fn visualization_section(entity: &EntityType) -> Option<PropSection> {
             | EntityType::Seqend(_)
             | EntityType::Leader(_)
             | EntityType::Wipeout(_)
-            // The reference lists no 3D group for an underlay.
+            // The reference lists no 3D group for an underlay; a point
+            // cloud's is its own (stylization and colour scheme).
             | EntityType::Underlay(_)
             | EntityType::Unknown(_)
             // Non-plotting drawing-view border: never rendered, no properties.
             | EntityType::ViewBorder(_)
+    ) || matches!(
+        entity,
+        EntityType::Extended(extended)
+            if matches!(extended.data, codec::entities::ExtendedEntityData::PointCloudEx(_))
     ) {
         return None;
     }