Pick-result handler for the GPU picking → hover-overlay pipeline.
Builds the async callback handed to new PickingSystem(...) in
core/app.ts::initPicking. The handler maps a PickResult | null
to label + key + image-URL lookups and forwards the composed payload to
OverlayManager.updateHoverContent.
Extracted from core/app.ts so the branch logic (null result,
any combination of label/key/image content, no content, fetch failure,
or missing loaders) can be unit-tested with stub ports instead of a real
PickingSystem + zarr-backed loaders.
Pick-result handler for the GPU picking → hover-overlay pipeline.
Builds the async callback handed to
new PickingSystem(...)incore/app.ts::initPicking. The handler maps aPickResult | nullto label + key + image-URL lookups and forwards the composed payload toOverlayManager.updateHoverContent.Extracted from
core/app.tsso the branch logic (null result, any combination of label/key/image content, no content, fetch failure, or missing loaders) can be unit-tested with stub ports instead of a realPickingSystem+ zarr-backed loaders.