New tier-3 slice: a generic, brand-free OS-style shell framework. One <AppShell manifest> wrapper provider gives any project a macOS-style window manager (drag/snap/maximize, dock with macOS click-to-focus + hover window switcher, menu bar, ⌘K Spotlight) AND an iOS-style mobile surface (home pager, app library, control center, widgets). Everything project-specific arrives through the manifest: brand, apps, features, surface regions, capabilities (data/auth/AI injection seam), persistence, keymap. The five shell features (search, inspector, notifications, control-center, widgets) ship bundled inside the slice as defineFeature() contributions that mount into named <Slot>s — `rr add appshell` installs the whole shell as one unit. Responsiveness is a single ResponsiveProvider + 4 DRY primitives (AppFrame, MasterDetail, ResponsiveToolbar, TouchList). Lift hardening: the slice was made fully self-contained (imports nothing but @/components/ui/* + @/lib/utils — ResponsiveDialog and a graceful useIsMobile were pulled in-slice), and four oversized files were split under the 200-LOC cap (store, responsive-dialog, menu-bar, mobile-app-library). Source: os-vps (Topside).