Hypersurface LOD upgrade

[Birdasaur]

Update management of current FeatureCollection so that Hypersurface can project 4k or higher images/data grids. Currently large grids over 2048 in size will cause a series of gnarly GPU pipeline bugs and out of memory exceptions due to the huge internal buffers that would have to be allocated. A solution is to implement a LOD manager so that the entire image/grid is broken up into a pyramid.

Phase 1 — primitives + capped L0

1. Add primitive HeightField
2. Replace dataGrid/originalGrid usage in sampling path
3. Build L0Processed (aspect-preserving, max 2048)
4. Render only L0 (fixed)

Success criteria: 4K loads without crashing; interaction is stable.

Phase 2 — processed pyramid + screen-space LOD switching

1. Build L1/L2… down to 512
2. Implement pixelsPerCell heuristic
3. Hook into scroll/zoom/drag with throttling
4. Switch active LOD and rebuild mesh only on LOD changes

Success criteria: zooming out reduces mesh complexity; camera remains smooth.