fix(plugin_api): gate hatch validation test on host feature

Commit 98b56ef6 ('Complete Hatch host model coverage') added the hatch_geometry_and_boundaries_are_validated test without the #[cfg(feature = host)] guard, and commit f537aff7 imported codec directly instead of through crate::host::codec. This broke cargo test --workspace with 20 compilation errors because codec and the canvas validation helpers are only compiled when the host feature is active.

Fixes regression from commit 98b56ef673.

crates/ocs_plugin_api/src/entity_coverage.rs

@@ -3412,9 +3412,13 @@ mod tests {
                 .contains("no whitespace")
         );
     }
+    #[cfg(feature = "host")]
     #[test]
     fn hatch_geometry_and_boundaries_are_validated() {
-        use codec::entities::hatch::{BoundaryEdge, BoundaryPath, LineEdge};
+        use crate::host::codec::{
+            self,
+            entities::hatch::{BoundaryEdge, BoundaryPath, LineEdge},
+        };
         let mut hatch = codec::entities::Hatch::new();
         let mut path = BoundaryPath::new();
         for (start, end) in [