Use Batched Vector Primitives in KMZ Loader

### Feature

Today the KMZ loader tries to create a new entity for every vector in the file. For KMZ/KML files that define large numbers of vectors this can result in OOM conditions. It is possible to intercept these loading functions and use the new batched vector primitives to successfully load the data; it would be great for the KMZ loader to do this natively.

### AI acknowledgment

- [ ] I used AI to generate this feature request.
- [ ] (If the above is checked) I have reviewed the AI-generated content before submitting.

Start by tracing the KMZ loader's vector-loading functions and the new batched vector primitives they can use. Confirm the behavior with a KMZ/KML file containing many vectors; done means the loader uses batching natively and avoids out-of-memory conditions.

Written by the indexing model from the issue text.