Improve file writing and activity replay

frontend/app/components/assistant-ui/activity-panel.tsx

@@ -174,9 +174,17 @@ export function ActivityPanel() {
 		(activeSessionId !== replayedSessionId || hasActiveRun(liveRunStatus));
 	const items = shouldUseLiveItems ? liveItems : messageItems;
 	const selectedMessageId = selectedId ? activityMessageId(selectedId) : null;
-	const visibleItems = selectedMessageId
+	const selectedItems = selectedMessageId
 		? items.filter((item) => activityMessageId(item.id) === selectedMessageId)
-		: items;
+		: [];
+	const visibleItems =
+		selectedMessageId && selectedItems.length > 0 ? selectedItems : items;
+	const selectedActivityMissing = Boolean(
+		selectedMessageId &&
+			!shouldUseLiveItems &&
+			items.length > 0 &&
+			selectedItems.length === 0,
+	);
 	const prevLatestIdRef = useRef<string | null>(null);
 
 	useEffect(() => {
@@ -248,6 +256,11 @@ export function ActivityPanel() {
 					</p>
 				) : (
 					<div className="flex flex-col gap-2">
+						{selectedActivityMissing ? (
+							<p className="rounded-md bg-muted/50 px-3 py-2 text-muted-foreground text-xs">
+								刷新后未能精确定位到这条摘要，已显示当前会话可恢复的活动链路。
+							</p>
+						) : null}
 						{visibleItems.map((item) => (
 							<ActivityPanelItem
 								key={item.id}