Module data/loaders

Unified Loader Architecture - Shared Components

Foundation for the unified spatial-index loader architecture, shared by the Points, Lines, and GSplats loaders, plus label-picking and overlay loaders. The mesh whole-node loader is not spatial-indexed but still consumes the RangeLoader and the color helpers from here.

Subpackages:

• spatial-query/ — chunk-bounds probe, tolerance computer, AABB query builder, chunk-boundary prefetch planner, and encoding-dispatching range loader.
• picking/ — label and image-label loaders consumed by core/app/picking.
• overlays/ — overlay config loader consumed by the overlay manager.

Root-level files:

• base-types.ts — canonical shared types (BaseViewState, LoadRange, …).
• color-loader.ts — color-attribute encode/decode shared by the three spatial-index loaders and the mesh whole-node loader.
• chunk-bounds-loader.ts — zarr chunk-bounds probe (layer below spatial-query).
• element-ids.ts — slot → on-disk element index map composition, shared by the Points, GSplats and Lines projections (picking's label lookup). For Lines it supplies only the local→on-disk vertex link of a longer chain; see data/scene-loader/process/data-processor-lines.ts.
• loader-metrics.ts, monitor-events.ts, once-init.ts, extend-to-all-preflight.ts — small cross-cutting helpers used by every spatial loader.

External callers should import from this barrel rather than reaching into deep paths so subpackage internals can move without callsite churn.