fix(pi): recover from Works prompt rejection

tests/unit/coding-chat-panel.test.tsx

@@ -519,6 +519,49 @@ describe('CodingChatPanel first Conversation', () => {
     expect(screen.getByRole('button', { name: '发送' })).toBeEnabled();
   });
 
+  it('reenables the same Conversation after a definite prompt rejection', async () => {
+    projectApi.list.mockResolvedValue({ projects: [project], activeProjectId: project.id });
+    projectApi.config.mockResolvedValue({ project, config });
+    projectApi.conversations.mockResolvedValue([conversation]);
+    conversationApi.events.mockResolvedValue(new FakeEventSource() as unknown as EventSource);
+    conversationApi.recover.mockResolvedValue(undefined);
+    conversationApi.submit
+      .mockRejectedValueOnce(new Error('所选模型当前不可用，请重新选择。'))
+      .mockImplementationOnce(async (input: {
+        conversationId: string;
+        clientRequestId: string;
+        mode: 'prompt';
+      }) => ({
+        accepted: true,
+        conversationId: input.conversationId,
+        clientRequestId: input.clientRequestId,
+        runId: 'run-retry',
+        mode: input.mode,
+      }));
+    const { CodingChatPanel } = await import('@/pages/Chat/CodingChatPanel');
+    const { createLocalConversationSnapshot } = await import('@/pages/Chat/coding-chat-snapshot');
+    const { codingConversationStore } = await import('@/stores/coding-conversations');
+    conversationApi.snapshot.mockResolvedValue(createLocalConversationSnapshot(project.id, conversation));
+    render(<CodingChatPanel />);
+
+    const textbox = await screen.findByRole('textbox');
+    await waitFor(() => expect(codingConversationStore.getState().selectedConversationId)
+      .toBe(conversation.id));
+    fireEvent.change(textbox, { target: { value: 'First prompt' } });
+    await waitFor(() => expect(screen.getByRole('button', { name: '发送' })).toBeEnabled());
+    fireEvent.click(screen.getByRole('button', { name: '发送' }));
+
+    await waitFor(() => expect(textbox).toHaveValue('First prompt'));
+    expect(await screen.findByText('所选模型当前不可用，请重新选择。')).toBeInTheDocument();
+    expect(codingConversationStore.getState().entriesByConversationId[conversation.id]?.error)
+      .toBeNull();
+    expect(screen.queryByRole('button', { name: '重试' })).not.toBeInTheDocument();
+    fireEvent.change(textbox, { target: { value: 'Retry prompt' } });
+    await waitFor(() => expect(screen.getByRole('button', { name: '发送' })).toBeEnabled());
+    fireEvent.click(screen.getByRole('button', { name: '发送' }));
+    await waitFor(() => expect(conversationApi.submit).toHaveBeenCalledTimes(2));
+  });
+
   it('caps one message at 16 images and uploads at most four concurrently', async () => {
     projectApi.list.mockResolvedValue({ projects: [project], activeProjectId: project.id });
     projectApi.config.mockResolvedValue({ project, config });