Final MVP valid

lib/ui/screenlessMode.ts

@@ -0,0 +1,52 @@
+"use client";
+
+import { useEffect, useState } from "react";
+
+let current: boolean | null = null;
+let inflight: Promise<void> | null = null;
+const listeners = new Set<(next: boolean) => void>();
+
+function notify(next: boolean) {
+  current = next;
+  listeners.forEach((fn) => fn(next));
+}
+
+async function loadScreenlessMode() {
+  if (inflight) return inflight;
+  inflight = (async () => {
+    try {
+      const res = await fetch("/api/settings", { cache: "no-store" });
+      const data = await res.json().catch(() => ({}));
+      if (res.ok && data?.ok) {
+        const mode = data?.settings?.modules?.screenlessMode === true;
+        notify(mode);
+      }
+    } catch {
+      // ignore fetch failures; keep current state
+    } finally {
+      inflight = null;
+    }
+  })();
+  return inflight;
+}
+
+export function useScreenlessMode() {
+  const [screenlessMode, setScreenlessMode] = useState(current ?? false);
+
+  useEffect(() => {
+    listeners.add(setScreenlessMode);
+    return () => {
+      listeners.delete(setScreenlessMode);
+    };
+  }, []);
+
+  useEffect(() => {
+    void loadScreenlessMode();
+  }, []);
+
+  function set(next: boolean) {
+    notify(next);
+  }
+
+  return { screenlessMode, setScreenlessMode: set };
+}