优化 DirectProject 增量历史累积

仅在 DirectProject 模式记录增量文本

避免其他工作区为每个事件创建无用副本

apps/ai-game-creator-shell/src-tauri/src/agent/codex_app_server.rs

@@ -2278,7 +2278,9 @@ impl CodexAppServerConnection {
                 };
                 match event {
                     Some(CodexTurnEvent::AgentMessageDelta { item_id, delta }) => {
+                        if self.inner.workspace_mode == CodexAppServerWorkspaceMode::DirectProject {
                             direct_project_history.observe_delta(&item_id, &delta);
+                        }
                         streamed_text.push_str(&delta);
                         if let Some(observer) = direct_observer.as_deref_mut() {
                             observer(DirectCodexTurnObservation::AccumulatedText(