fix: preserve chat order and published page scripts

chat-finish-sync.test.mjs

@@ -52,3 +52,31 @@ test('mergeSessionMessagesAfterFinish matches Finish sync merge semantics', () =
     ['u1', 'a1'],
   );
 });
+
+test('mergeConversationSnapshot keeps an omitted middle message between its anchors', () => {
+  const local = [
+    msg('u1', 'user', '第一轮'),
+    msg('a1', 'assistant', '第一轮回复'),
+    msg('u2', 'user', '第二轮'),
+    msg('a2', 'assistant', '第二轮回复'),
+  ];
+  const server = [local[0], local[1], local[3]];
+  assert.deepEqual(
+    mergeConversationSnapshot(local, server).map((message) => message.id),
+    ['u1', 'a1', 'u2', 'a2'],
+  );
+});
+
+test('mergeConversationSnapshot keeps local messages before the first and after the last server anchor', () => {
+  const local = [
+    msg('u0', 'user', '本地前置'),
+    msg('u1', 'user', '服务端消息'),
+    msg('a1', 'assistant', '服务端回复'),
+    msg('a2', 'assistant', '本地尾部'),
+  ];
+  const server = [local[1], local[2]];
+  assert.deepEqual(
+    mergeConversationSnapshot(local, server).map((message) => message.id),
+    ['u0', 'u1', 'a1', 'a2'],
+  );
+});