Complete Region: create from a profile, plus tuple and int friendliness

RegionFromProfile reuses the REGION command's kernel calls; doc.solids.region
exposes it with layer and delete_source options. The lifecycle test builds
regions from real circle and polyline entities and covers refusals, a move,
both formats and undo. create_entity now accepts coordinate tuples for point
properties and every generated float setter accepts Python ints.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

crates/ocs_plugin_api/src/ipc/v4/protocol.rs

@@ -114,6 +114,7 @@ mod tests {
                 layer: Some("SOLIDS".into()),
             },
             SolidOperation::Transform { handle: acadrust::Handle::new(7), matrix: [1.0; 16] },
+            SolidOperation::RegionFromProfile { source: acadrust::Handle::new(3), layer: None, delete_source: true },
         ] {
             let bytes = bincode::serialize(&PluginRequest::SolidOperation { operation: operation.clone() }).unwrap();
             assert!(matches!(bincode::deserialize::<PluginRequest>(&bytes).unwrap(),