Fix narrow PWA layout on tablet with standalone width rules.

Allow any orientation in manifest, widen content and enable dual-column mode in installed apps on tablet viewports, with iOS display-mode fallback.

Co-authored-by: Cursor <cursoragent@cursor.com>

components/page-shell.tsx

@@ -27,7 +27,8 @@ export default function PageShell({
       <Header />
       <main
         className={cn(
-          "mx-auto flex w-full flex-1 flex-col border-border/40 bg-background sm:border-x",
+          "site-content-shell mx-auto flex w-full flex-1 flex-col border-border/40 bg-background sm:border-x",
+          width === "narrow" && "site-content-shell-narrow",
           SHELL_WIDTH[width],
           className,
         )}