fix(chat): recover active requests and preserve finish order

chat-finish-sync.test.mjs

@@ -80,3 +80,33 @@ test('mergeConversationSnapshot keeps local messages before the first and after
     ['u0', 'u1', 'a1', 'a2'],
   );
 });
+
+test('mergeConversationSnapshot keeps local-only messages at their streamed position', () => {
+  const local = [
+    msg('u1', 'user', '生成页面'),
+    msg('a1', 'assistant', '开始分析'),
+    msg('a2', 'assistant', '调用工具'),
+    msg('a3', 'assistant', '页面完成'),
+  ];
+  const server = [
+    msg('u1', 'user', '生成页面'),
+    msg('a3', 'assistant', '页面完成（服务端）'),
+  ];
+  const merged = mergeConversationSnapshot(local, server);
+  assert.deepEqual(merged.map((message) => message.id), ['u1', 'a1', 'a2', 'a3']);
+  assert.equal(merged[3].content[0].text, '页面完成（服务端）');
+});
+
+test('mergeConversationSnapshot preserves multiple local messages before the next server anchor', () => {
+  const local = [
+    msg('u1', 'user', '任务'),
+    msg('a1', 'assistant', '步骤一'),
+    msg('a2', 'assistant', '步骤二'),
+    msg('a3', 'assistant', '完成'),
+  ];
+  const server = [msg('u1', 'user', '任务'), msg('a3', 'assistant', '完成')];
+  assert.deepEqual(
+    mergeConversationSnapshot(local, server).map((message) => message.id),
+    ['u1', 'a1', 'a2', 'a3'],
+  );
+});