补充 DirectProject 历史读取错误提示

捕获历史切片读取失败并保留加载状态清理。

apps/ai-game-creator-shell/src/App.tsx

@@ -11931,6 +11931,10 @@ export function App({
           directHistoryOldestItemIdRef.current =
             older.find((message) => message.messageId)?.messageId ??
             directHistoryOldestItemIdRef.current;
+        } catch (error) {
+          setWorkspaceStatus(
+            `读取更早的对话历史失败：${error instanceof Error ? error.message : String(error)}`,
+          );
         } finally {
           directHistoryLoadingRef.current = false;
         }