feat: handle status events to create assistant placeholder early

frontend/components/gemini/GeminiChat.tsx

@@ -332,6 +332,23 @@ export function GeminiChat() {
             })
           );
 
+        } else if (event.type === "status") {
+          // status 事件：确保 assistant 消息占位符已存在（trace 面板早于 token 出现）
+          setConversations((prev) =>
+            prev.map((c) => {
+              if (c.id !== streamConvId) return c;
+              const exists = c.messages.some((m) => m.id === aiMsgId);
+              if (exists) return c;
+              return {
+                ...c,
+                messages: [
+                  ...c.messages,
+                  { id: aiMsgId, role: "assistant" as const, content: "", timestamp: new Date(), traceItems: [] },
+                ],
+              };
+            })
+          );
+
         } else if (event.type === "tool_start" && event.tool) {
           const item: TraceItem = {
             id: event.call_id ?? `${event.tool}-${event.ts ?? Date.now()}`,
@@ -447,6 +464,23 @@ export function GeminiChat() {
                 };
               })
             );
+          } else if (event.type === "status") {
+            // status 事件：确保 assistant 消息占位符已存在（trace 面板早于 token 出现）
+            setConversations((prev) =>
+              prev.map((c) => {
+                if (c.id !== regenConvId) return c;
+                const exists = c.messages.some((m) => m.id === newAiMsgId);
+                if (exists) return c;
+                return {
+                  ...c,
+                  messages: [
+                    ...c.messages,
+                    { id: newAiMsgId, role: "assistant" as const, content: "", timestamp: new Date(), traceItems: [] },
+                  ],
+                };
+              })
+            );
+
           } else if (event.type === "tool_start" && event.tool) {
             const item: TraceItem = {
               id: event.call_id ?? `${event.tool}-${event.ts ?? Date.now()}`,