fix: 修复嵌套 iframe 污染 embed 会话与协助卡后流式显示异常

顶层窗口通过 topOwned 标记自愈老版嵌套页写脏的 embed.session；协助卡提交后避免冻结 checkpoint 覆盖实时 SSE，并仅在服务端回显新 human 消息时清除乐观气泡。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend-web/src/core/embed/embed-session.test.ts

@@ -97,6 +97,51 @@ test("nested embed=1 does not hide chrome on the same-origin top window", () =>
   });
 });
 
+test("top parent reclaims pollution from an old nested iframe (no topOwned)", () => {
+  withSharedTab(({ storage, asTop }) => {
+    asTop();
+    syncEmbedSessionFromSearch("");
+    // 模拟未升级的老版内层：仍写共用键且没有 topOwned。
+    storage.setItem(
+      "embed.session",
+      JSON.stringify({
+        embed: true,
+        theme: "light",
+        hideJump: false,
+        hideHeader: false,
+        hideChrome: false,
+        isolate: false,
+      }),
+    );
+
+    // 外层点菜单重算布局时会读 session —— 必须立刻自愈。
+    assert.equal(isEmbedActive(), false);
+    assert.equal(isChromeHidden(), false);
+    assert.equal(storage.getItem("embed.session"), null);
+  });
+});
+
+test("top sync after old nested pollution does not mark owner", () => {
+  withSharedTab(({ storage, asTop }) => {
+    asTop();
+    storage.setItem(
+      "embed.session",
+      JSON.stringify({
+        embed: true,
+        theme: "light",
+        hideJump: false,
+        hideHeader: false,
+        hideChrome: false,
+        isolate: false,
+      }),
+    );
+    syncEmbedSessionFromSearch("");
+    assert.equal(isEmbedActive(), false);
+    assert.equal(isChromeHidden(), false);
+    assert.equal(storage.getItem("embed.session"), null);
+  });
+});
+
 test("nested iframe reclaims a polluted shared embed.session key", () => {
   withSharedTab(({ storage, asTop, asIframe }) => {
     asTop();
@@ -111,7 +156,6 @@ test("nested iframe reclaims a polluted shared embed.session key", () => {
         isolate: false,
       }),
     );
-    assert.equal(isEmbedActive(), true);
 
     asIframe();
     syncEmbedSessionFromSearch("?embed=1");
@@ -129,6 +173,7 @@ test("nested iframe keeps the top window's own embed session", () => {
     syncEmbedSessionFromSearch("?embed=1&theme=dark");
     syncEmbedSessionFromSearch("");
     assert.equal(isEmbedActive(), true);
+    assert.equal(readEmbedSession()?.topOwned, true);
 
     asIframe();
     syncEmbedSessionFromSearch("?embed=1");
@@ -162,3 +207,22 @@ test("nested reclaim strips embed but keeps top isolate", () => {
     assert.equal(isIsolatedSession(), true);
   });
 });
+
+test("top reclaim strips embed but keeps isolate without nested help", () => {
+  withSharedTab(({ storage, asTop }) => {
+    asTop();
+    storage.setItem(
+      "embed.session",
+      JSON.stringify({
+        embed: true,
+        theme: "light",
+        hideJump: false,
+        hideHeader: false,
+        hideChrome: false,
+        isolate: true,
+      }),
+    );
+    assert.equal(isEmbedActive(), false);
+    assert.equal(isIsolatedSession(), true);
+  });
+});