继续收口暗色弹窗底部动作区

新增 PlatformDarkModalFooter 统一 dark modal footer 的布局壳
接入 NPC 弹窗、选择定制弹窗、任务更新弹层与物品详情 footer
补充组件级与弹窗集成测试并更新收口计划和共享决策记录

src/components/SelectionCustomizationModals.test.tsx

@@ -31,6 +31,7 @@ test('角色自定义错误提示复用暗色 PlatformStatusMessage chrome', ()
   const currentCharacterPanel = screen.getByText('当前角色：试剑客');
   const nameInput = screen.getByLabelText('角色名字');
   const backstoryTextarea = screen.getByLabelText('背景补充');
+  const footer = screen.getByTestId('selection-modal-footer');
 
   expect(errorMessage.className).toContain('platform-status-message');
   expect(errorMessage.className).toContain('border-rose-300/15');
@@ -53,6 +54,8 @@ test('角色自定义错误提示复用暗色 PlatformStatusMessage chrome', ()
   expect(closeButton.className).toContain(
     'platform-modal-close-button--editor-dark',
   );
+  expect(footer.className).toContain('platform-dark-modal-footer');
+  expect(footer.className).toContain('border-t');
   expect(currentCharacterPanel.className).toContain('border-white/10');
   expect(currentCharacterPanel.className).toContain('bg-black/25');
 });