fix: eliminate queue tab flash on mobile by using useSyncExternalStore

useMediaQuery initialized to false and updated in useEffect, causing a
paint where isMobile was false on mobile devices. This rendered the
desktop layout first, hiding the queue tab until the effect fired.

useSyncExternalStore reads matchMedia synchronously on the client so
the correct layout is used on the first render with no extra paint.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/hooks/useMediaQuery.ts

@@ -1,15 +1,13 @@
-import { useState, useEffect } from "react";
+import { useSyncExternalStore } from "react";
 
 export function useMediaQuery(query: string): boolean {
-  const [matches, setMatches] = useState(false);
-
-  useEffect(() => {
-    const mq = window.matchMedia(query);
-    setMatches(mq.matches);
-    const handler = (e: MediaQueryListEvent) => setMatches(e.matches);
-    mq.addEventListener("change", handler);
-    return () => mq.removeEventListener("change", handler);
-  }, [query]);
-
-  return matches;
+  return useSyncExternalStore(
+    (callback) => {
+      const mq = window.matchMedia(query);
+      mq.addEventListener("change", callback);
+      return () => mq.removeEventListener("change", callback);
+    },
+    () => window.matchMedia(query).matches,
+    () => false
+  );
 }