继续沉淀结果页返回按钮

新增共享 PlatformBackActionButton 承接结果页轻量返回入口
将拼图方洞拼消消视觉小说等结果页返回按钮收口到共享组件
将拼消消跳一跳敲木鱼宝贝识物结果页返回按钮收口到共享组件
补充对应测试并更新 PlatformUiKit 收口计划与共享决策记录

src/components/puzzle-result/PuzzleResultView.test.tsx

@@ -100,6 +100,29 @@ test('renders missing draft notice with shared PlatformEmptyState chrome', () =>
   expect(noticePanel?.className).toContain('text-[var(--platform-text-soft)]');
 });
 
+test('renders shared compact back action button in result header', () => {
+  const onBack = vi.fn();
+
+  render(
+    <PuzzleResultView
+      session={createSession()}
+      onBack={onBack}
+      onExecuteAction={() => {}}
+    />,
+  );
+
+  const backButton = screen.getByRole('button', { name: '返回' });
+
+  expect(backButton.className).toContain('platform-button--ghost');
+  expect(backButton.className).toContain('text-[11px]');
+  expect(backButton.className).toContain('gap-1.5');
+  expect(backButton.querySelector('svg')?.className.baseVal).toContain('h-3.5');
+
+  fireEvent.click(backButton);
+
+  expect(onBack).toHaveBeenCalledTimes(1);
+});
+
 function createSession(
   overrides: Partial<PuzzleAgentSessionSnapshot> = {},
 ): PuzzleAgentSessionSnapshot {