Twin: DOM labels (binding chips, plant labels, zone readouts) pile up and clip at the viewport edge – no collision, leader lines or edge clamping

FIXED 2026-09-14 (branch fix/twin-picks-labels, awaiting commit): all twin labels (zone readouts, plant labels, placed-sensor labels, binding chips, MODEL PENDING, hover) now go through twin/labels.ts + twin/LabelLayer.tsx: a registry with a per-frame screen-space layout (priority order, greedy collision push, stage-edge clamp, off-screen hide, chips hidden beyond 6.5 m, SVG leader line whenever a label is moved off its anchor). drei Html is no longer used in the twin. Verified at Room / 2×4 / Root presets in the preview pane. — ORIGINAL: At the 2×4 camera preset five binding chips stack on the left edge of the stage, half off-screen and overlapping each other and the plant labels; at the Canopy preset the two plant labels overlap. Labels were drei Html anchored to a world point with no collision avoidance, leader lines, clustering or screen-edge clamping, and no density policy by camera distance.