更新依赖，优化认证流程；添加聊天框动画效果，优化消息处理逻辑

src/lib/chatStream.test.ts

@@ -78,4 +78,23 @@ describe("streamCopilotChat", () => {
       { type: "error", message: "stream request failed", detail: "bad request" },
     ]);
   });
+
+  it("emits re-login message on unauthorized response", async () => {
+    apiFetch.mockResolvedValue({
+      ok: false,
+      status: 401,
+      body: null,
+      text: async () => "unauthorized",
+    });
+
+    const events: Array<{ type: string; message?: string; detail?: string }> = [];
+    await streamCopilotChat({
+      message: "hi",
+      onEvent: (event) => events.push(event),
+    });
+
+    expect(events).toEqual([
+      { type: "error", message: "Login expired. Please sign in again.", detail: undefined },
+    ]);
+  });
 });