brand: fix remaining stale mark viewBoxes in atmosphere-2026 deck
Update 4 additional vit-mark instances (0 0 32 32 → 3.375 2.5 25.25 25.25)
on slides 4-7 of atmosphere-2026 that were missed in the first pass.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>