Some labels (clustered nodes: Flux, The signifier rules the subject,
The body as window onto the thing-in-itself) appeared later in zoom than
others, without fade. Root cause: sigma's label grid — viewport cells
of labelGridCellSize (100px default) compete, only ceil(labelDensity /
ratio^2) winners per cell draw (one at fit with default density 1) —
so clustered nodes' labels were culled until zoom changed the quota,
then popped in with the global fade already complete.
labelDensity: MAX_SAFE_INTEGER turns the quota off. The camera-ratio
gate (LABELS_CAMERA_RATIO + LABELS_FADE_SPAN) is now the ONLY label
culling: every label appears at the same zoom with the same fade —
the wave-1 'all labels at once' intent, finally true.
Verified pixel-level at fit view: all 31 node labels render, including
the three previously-missing ones; no console errors.