The defaults were calibrated in the screen-fixed era; world-scaling renders
sizes at setting x k/kFit, so at the default label gate (2x fit) everything
read ~2x too big ("labels way too large even at the minimum"). Fit-zoom
normalizes layout scale away, so the fix belongs in sizes, not layout:
spreading nodes further apart in world units changes nothing at fit.
- Defaults: nodeSize 6 -> 4, arrowLength 5 -> 4, labelSize 12 -> 7.
- Clamps/slider ranges widened at the low end: nodeSize 1-14 (step 0.5),
edgeWidth 0.25-4 (step 0.25), arrowLength 1-15 (step 0.5),
labelSize 3-24 (step 0.5).
- GLOW_PAD 9 -> 6 (halo dominated small discs), REGION_LABEL_SIZE 18 -> 14.
- Tests updated for the new clamp bounds plus a low-end pass-through case
(403/403). The saved render-settings.json still shadows defaults by
design; the local copy was reset so the new defaults showed immediately.