fix(core): ai message resending (#13359)

Close [AI-395](https://linear.app/affine-design/issue/AI-395)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Bug Fixes**
* Improved chat stability by resetting chat action signals after
processing to prevent repeated triggers.

* **New Features**
* Added end-to-end tests for new chat session creation and chat pinning
functionality to enhance reliability.

* **Enhancements**
* Enhanced chat toolbar with test identifiers and pinned state
attributes for better accessibility and testing.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Co-authored-by: fengmk2 <fengmk2@gmail.com>

tests/affine-cloud-copilot/e2e/basic/chat.spec.ts

@@ -450,4 +450,89 @@ test.describe('AIBasic/Chat', () => {
       },
     ]);
   });
+
+  test('should support create a new chat after ask ai', async ({
+    loggedInPage: page,
+    utils,
+  }) => {
+    await utils.chatPanel.closeChatPanel(page);
+    await utils.editor.askAIWithText(
+      page,
+      'AFFiNE is an open source all in one workspace.'
+    );
+    await page.keyboard.type('Translate to chinese.');
+
+    const sendButton = await page.getByTestId('ai-panel-input-send');
+    await expect(sendButton).toHaveAttribute('data-active', 'true');
+    await sendButton.click();
+
+    await expect(page.getByTestId('sidebar-tab-content-chat')).toBeVisible();
+    await utils.chatPanel.waitForHistory(page, [
+      {
+        role: 'user',
+        content:
+          'AFFiNE is an open source all in one workspace.\nTranslate to chinese.',
+      },
+      {
+        role: 'assistant',
+        status: 'success',
+      },
+    ]);
+
+    await page.getByTestId('ai-panel-new-chat').click();
+    await page.waitForTimeout(1000);
+    await utils.chatPanel.expectToHaveHistory(page, []);
+  });
+
+  test('should support pin chat', async ({ loggedInPage: page, utils }) => {
+    await utils.chatPanel.openChatPanel(page);
+    await utils.chatPanel.makeChat(
+      page,
+      'Hello, how can you help me? Answer in 50 words.'
+    );
+
+    await utils.chatPanel.waitForHistory(page, [
+      {
+        role: 'user',
+        content: 'Hello, how can you help me? Answer in 50 words.',
+      },
+      {
+        role: 'assistant',
+        status: 'success',
+      },
+    ]);
+
+    // pinned
+    await expect(page.getByTestId('ai-panel-pin-chat')).toHaveAttribute(
+      'data-pinned',
+      'false'
+    );
+    await page.getByTestId('ai-panel-pin-chat').click();
+    await expect(page.getByTestId('ai-panel-pin-chat')).toHaveAttribute(
+      'data-pinned',
+      'true'
+    );
+
+    // create new doc
+    await utils.editor.createDoc(page, 'Doc 1', 'doc1');
+    await utils.chatPanel.expectToHaveHistory(page, [
+      {
+        role: 'user',
+        content: 'Hello, how can you help me? Answer in 50 words.',
+      },
+      {
+        role: 'assistant',
+        status: 'idle',
+      },
+    ]);
+    await page.getByTestId('ai-panel-pin-chat').click();
+
+    // unpinned
+    await expect(page.getByTestId('ai-panel-pin-chat')).toHaveAttribute(
+      'data-pinned',
+      'false'
+    );
+    await utils.editor.createDoc(page, 'Doc 2', 'doc2');
+    await utils.chatPanel.expectToHaveHistory(page, []);
+  });
 });