Map Viewport in the Python host model

Curated view fields are writable; the owner must be a paper-space block and
frozen layers must exist. staged_python_viewport_lifecycle_over_real_ipc
passes every gate except a paper-space canvas oracle, so the kind is
recorded as integration-tested.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

plugins/opencad-python/src/ocs_module.rs

@@ -4756,7 +4756,7 @@ mod tests {
                 );
             }
         }
-        assert_eq!(emitted.len(), 34);
+        assert_eq!(emitted.len(), 35);
     }
 
     #[cfg(feature = "experimental-host-model")]