Restore Calmstorm's nav-chrome elegance as themable shell primitives (separate structure/behavior from styling)
@dididecks/shell v0.1's PlayChrome solved the navigation contract but discarded calmstorm-decks' deliberately elegant chrome — floating bottom-right capsule, glassy white/grey/black, fade-on-idle, two-axis nav (variant cycling + section walking), custom tooltips, tabular-num counter — and replaced it with a heavy dark bottom bar that always claims viewport real-estate. This plan lifts the calmstorm chrome forward as package-level primitives in apps/deck-shell/, with structure and behavior cleanly separated from visual styling via a CSS-custom-property theming contract. Consumers (chroma-decks today; future client sites tomorrow) inherit a sensible neutral default (calmstorm's plain white/grey/black) when client-specific tokens aren't supplied, and override with their own design system when they are. Hybrid of port-and-replace + re-skin: port the bones, ship the calmstorm look as the universal fallback, then let chroma-decks (and others) light them up with their own brand.