HeatmapLayer rendering severely wrong in interleaved Maplibre rendering

Editing from the duckdb example: https://github.com/developmentseed/lonboard/blob/fe4e1f7c34f0dcda347156212d683688675b1e85/examples/duckdb.ipynb

```py
basemap = MaplibreBasemap(mode="interleaved", style=CartoStyle.Positron)
layer = HeatmapLayer.from_duckdb(con.table("rides"), con, before_id="watername_ocean")
m = Map(layer, height=700, basemap=basemap)
m
```

https://github.com/user-attachments/assets/9f9d36f1-e38d-42a6-8f9c-a47193c0f5cc

Everything looks fine in overlaid mode:
```
m = Map(layer, height=700, basemap=MaplibreBasemap(mode="overlaid", style=CartoStyle.Positron))
m
```

Start with examples/duckdb.ipynb and run the supplied HeatmapLayer example using MaplibreBasemap in interleaved mode, then compare it with overlaid mode. Investigate the rendering path involved in interleaved Maplibre integration; done means the heatmap renders correctly in interleaved mode without regressing the overlaid example.

Written by the indexing model from the issue text.