Vector Tiles: Clip to tile bounding volumes

### Feature

Support clipping vector collections to tile bounding volumes. This must be done in the fragment shader, so that wide lines are visible within tile extents, even if the underlying geometry has passed slightly outside the tile. See https://github.com/CesiumGS/3d-tiles/pull/838.

### 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 vector collection rendering into the fragment shader and identify where tile bounding volumes are available. Compare the intended behavior with the linked 3d-tiles pull request. Done means clipping occurs in the fragment shader while wide lines remain visible within tile extents.

Written by the indexing model from the issue text.