arena: stack top-right HUD into 6 labeled, non-overlapping sections
GFX/CAM/STATE/SPEED/PERF/NET each get their own row range so the
network info and perf panel no longer collide. Adds a rightLabelMulti
helper so labels and values can be tinted independently per row.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>