Suppress photo-frame idle while Media overlay is open

Jellyfin runs in a cross-origin iframe so we can't observe the video
element's play state directly — using overlay-open as the proxy. Any
user activity still resets the timer, and Controls / Cameras / Settings
overlays still fall to idle as before.

src/hooks/useIdle.ts

@@ -4,6 +4,9 @@ import { useUIStore } from '@/stores/uiStore';
 /**
  * Tracks touch/mouse/keyboard activity. After `timeoutMs` of no activity,
  * flips the UI into idle mode (photo frame). Any activity exits idle.
+ * Idle is also suppressed while the Media overlay is open (Jellyfin runs
+ * in a cross-origin iframe, so we can't observe the video element's
+ * play state directly — the overlay being open is our proxy).
  */
 export function useIdle(timeoutMs: number) {
   const isIdle = useUIStore((s) => s.isIdle);
@@ -14,10 +17,21 @@ export function useIdle(timeoutMs: number) {
 
     let timer: ReturnType<typeof setTimeout> | null = null;
 
-    const reset = () => {
+    const schedule = () => {
       if (timer) clearTimeout(timer);
+      timer = setTimeout(() => {
+        // Re-check at fire time so "media overlay open" is always current
+        if (useUIStore.getState().mediaOverlayOpen) {
+          schedule();
+          return;
+        }
+        setIdle(true);
+      }, timeoutMs);
+    };
+
+    const reset = () => {
       if (useUIStore.getState().isIdle) setIdle(false);
-      timer = setTimeout(() => setIdle(true), timeoutMs);
+      schedule();
     };
 
     const events: Array<keyof DocumentEventMap> = [
@@ -29,7 +43,7 @@ export function useIdle(timeoutMs: number) {
     ];
     for (const e of events) document.addEventListener(e, reset, { passive: true });
 
-    reset();
+    schedule();
 
     return () => {
       if (timer) clearTimeout(timer);