fix(design): restore streamed replies and quote handoff

tests/unit/youth-creation-card.test.tsx

@@ -1,4 +1,4 @@
-import { cleanup, fireEvent, render, screen, within } from '@testing-library/react';
+import { cleanup, fireEvent, render, screen, waitFor, within } from '@testing-library/react';
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 import { YouthCreationCard } from '@/pages/ImageCanvas/YouthCreationCard';
 import { DesignTaskPanel } from '@/pages/ImageCanvas/DesignProductionPanel';
@@ -21,12 +21,14 @@ function renderCard(
     quoteBlockers?: DesignCompilationIssue[];
     onOpenFineTune?: () => void;
     onFocusComposer?: () => void;
+    onQuoteOffered?: () => void;
   } = {},
 ) {
   const requestQuote = vi.fn().mockResolvedValue(workspace);
   const resolveDecisionPrompt = vi.fn().mockResolvedValue(workspace);
   const onOpenFineTune = options.onOpenFineTune ?? vi.fn();
   const onFocusComposer = options.onFocusComposer ?? vi.fn();
+  const onQuoteOffered = options.onQuoteOffered ?? vi.fn();
   useImageWorkspaceStore.setState({
     workspace,
     quoteBlockers: [],
@@ -41,6 +43,7 @@ function renderCard(
       generationAvailable={options.generationAvailable ?? true}
       onOpenFineTune={onOpenFineTune}
       onFocusComposer={onFocusComposer}
+      onQuoteOffered={onQuoteOffered}
     />,
   );
   return {
@@ -49,6 +52,7 @@ function renderCard(
     resolveDecisionPrompt,
     onOpenFineTune,
     onFocusComposer,
+    onQuoteOffered,
   };
 }
 
@@ -97,8 +101,8 @@ describe('YouthCreationCard', () => {
     vi.clearAllMocks();
   });
 
-  it('shows a plain creation summary and offers a youth-facing ready action', () => {
-    const { requestQuote } = renderCard();
+  it('shows a plain creation summary and reveals the offered quote after requesting it', async () => {
+    const { onQuoteOffered, requestQuote } = renderCard();
 
     expect(screen.getByRole('heading', { name: 'AI 听懂的想法' })).toBeInTheDocument();
     expect(screen.getByText('会跟着聊天自动更新，不需要逐项填写。')).toBeInTheDocument();
@@ -112,6 +116,7 @@ describe('YouthCreationCard', () => {
     fireEvent.click(screen.getByRole('button', { name: '看看制作方案' }));
 
     expect(requestQuote).toHaveBeenCalledOnce();
+    await waitFor(() => expect(onQuoteOffered).toHaveBeenCalledOnce());
   });
 
   it('does not surface legacy decision prompts as a form', () => {