iter(g27): 抽出弹层 Esc 栈，多弹层只关最上层

packages/skin/ui/src/modal.ts

@@ -1,5 +1,6 @@
 import { effect, h } from '@ui-arch/frame';
 import type { ModalProps } from './types.js';
+import { pushOverlay } from './overlay.js';
 
 /*** 弹窗：open 信号驱动显隐，点遮罩、× 或 Esc 触发 onClose；Tab 焦点陷阱 + 关闭归还焦点 ***/
 export function modal(props: ModalProps, ...children: unknown[]): HTMLElement {
@@ -23,6 +24,7 @@ export function modal(props: ModalProps, ...children: unknown[]): HTMLElement {
   );
   overlay.append(box);
   let lastFocus: HTMLElement | null = null; // 打开前焦点宿主，关闭时归还
+  let release: (() => void) | null = null; // Esc 栈注销函数，关闭时释放
   const focusables = (): HTMLElement[] =>
     Array.from(box.querySelectorAll<HTMLElement>('button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])'))
       .filter((el) => !el.hasAttribute('disabled')); // 弹窗内可聚焦元素（排除禁用）
@@ -31,9 +33,12 @@ export function modal(props: ModalProps, ...children: unknown[]): HTMLElement {
     overlay.classList.toggle('ua-open', open); // 显隐跟随信号
     if (open) {
       lastFocus = document.activeElement as HTMLElement | null; // 记录打开前焦点
+      release ??= pushOverlay(close); // 入 Esc 栈：多弹层时只关最上层
       (box.querySelector('button, input, textarea') as HTMLElement | null)?.focus(); // 打开时聚焦首个可交互元素
-    } else if (lastFocus) {
-      lastFocus.focus(); // 关闭时归还焦点
+    } else {
+      release?.(); // 出 Esc 栈
+      release = null;
+      lastFocus?.focus(); // 关闭时归还焦点
       lastFocus = null;
     }
   });
@@ -49,8 +54,5 @@ export function modal(props: ModalProps, ...children: unknown[]): HTMLElement {
       e.preventDefault(); first.focus(); // Tab 到末位时回绕到开头
     }
   });
-  document.addEventListener('keydown', (e: KeyboardEvent) => {
-    if (e.key === 'Escape' && props.open()) close(); // Esc 关闭当前打开的弹窗
-  });
   return overlay;
 }