fix(canvas): soften design conversation

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

@@ -120,9 +120,11 @@ describe('YouthCreationCard', () => {
     useImageWorkspaceStore.getState().reset();
   });
 
-  it('puts the editable creator prompt and compact visible parameters in one plan card', () => {
+  it('keeps the editable prompt and visible parameters in a lightweight inline plan', () => {
     renderCard();
 
+    expect(screen.getByTestId('youth-creation-card')).toHaveClass('py-2');
+    expect(screen.getByTestId('youth-creation-card')).not.toHaveClass('border', 'shadow-sm');
     expect(screen.getByRole('heading', { name: '制作方案' })).toBeInTheDocument();
     expect(screen.getByRole('textbox', { name: '创作提示词' })).toHaveValue(
       '把便携咖啡机呈现为城市通勤中的精密工具',
@@ -131,6 +133,7 @@ describe('YouthCreationCard', () => {
     expect(screen.getByRole('combobox', { name: '画幅' })).toHaveValue('3:4');
     expect(screen.getByRole('button', { name: '增加数量' })).toBeInTheDocument();
     expect(screen.getByRole('button', { name: '准备制作方案' })).toBeInTheDocument();
+    expect(screen.queryByRole('region', { name: '参考图' })).not.toBeInTheDocument();
     expect(screen.queryByText('查看画面细节')).not.toBeInTheDocument();
     expect(screen.queryByText('手动调整')).not.toBeInTheDocument();
   });