fix(media-grid): clear pending copy-url timers on unmount

src/components/admin/media-grid.tsx

@@ -33,6 +33,7 @@ export function AdminMediaGrid() {
 	const [copied, setCopied] = useState<string | null>(null);
 	const [error, setError] = useState<string | null>(null);
 	const fileRef = useRef<HTMLInputElement>(null);
+	const copyTimers = useRef<Set<ReturnType<typeof setTimeout>>>(new Set());
 
 	const load = useCallback(async () => {
 		setLoading(true);
@@ -40,6 +41,12 @@ export function AdminMediaGrid() {
 		setLoading(false);
 	}, []);
 
+	useEffect(() => {
+		return () => {
+			for (const t of copyTimers.current) clearTimeout(t);
+			copyTimers.current.clear();
+		};
+	}, []);
 	useEffect(() => {
 		load();
 	}, [load]);