fix(design): the table header takes the B9 fade utility, and every size is dvh, not vh (E28 S3d4)

The table header carried an arbitrary-value copy of fade-below; a contract refuses a hand gradient of a surface colour. 100vh is the viewport with a tablet browser's toolbar retracted, so h-screen / min-h-screen / static vh hid the last rows under it; a contract holds dvh (the Plex player stage changes with S3f, where it is played on the tablet).

frontend/src/components/ui/CommandPalette.tsx

@@ -173,7 +173,7 @@ function CommandPaletteBody({ onClose, groups }: { onClose: () => void; groups:
       const from = Math.max(activeIndex, 0);
       setPicked(flat[(from + step + flat.length) % flat.length]!.id);
     } else if (e.key === "PageDown" || e.key === "PageUp") {
-      // A page at a time, stopping at the ends (lib/listPaging). The list is 50vh and group headings
+      // A page at a time, stopping at the ends (lib/listPaging). The list is 50dvh and group headings
       // eat into it, so the page is measured. Home/End stay the field's own (caret to the query's ends).
       e.preventDefault();
       const list = listRef.current;
@@ -230,7 +230,7 @@ function CommandPaletteBody({ onClose, groups }: { onClose: () => void; groups:
         role="listbox"
         aria-label={t("palette.title")}
         hidden={flat.length === 0}
-        className="mt-3 max-h-[50vh] overflow-y-auto"
+        className="mt-3 max-h-[50dvh] overflow-y-auto"
       >
         {visible.map((g) => (
           <div