subagenttasks

Deck layout-system fix (v9): overflow-safe centering, density layer, verified in-browser

DONE 2026-07-03 by cwc-engineering after operator bug report (sizing/overlap/wrapping). ROOT CAUSE: justify-content:center on min-height:100vh flex slides — content grown past one viewport (v3-v8 layers) overflows upward into unreachable clipped space; scroll-snap mandatory traps tall slides. FIXES: (1) auto-margin centering trick (centers short slides, top-anchors tall — never clips), (2) snap mandatory→proximity, (3) eyebrow flex-wrap + 72px slideno clearance, (4) height-responsive density layer @max-height:900px (type scale, gaps, paddings, single-row g2 grids, compact ledes, hero band 20vh cap), (5) wrap-safety (overflow-wrap:anywhere) on chips/foot/small/ul per design system, (6) safe-area insets, (7) kbd-nav rect-based. VERIFIED with real browser via Preview harness at 1280x760 + 390x844: zero clipping, zero slideno collisions, zero horizontal overflow outside scroll containers, doc scrollW = viewport on mobile; tall slides 7→2 (max +6%, graceful); mobile screenshot visually confirmed. Deployed 86294384, lock recorded, artifact v9-layout-system-fix same URL.