修复工作区撤销重做快捷键

- 抽出 keyboardShortcuts helper，统一识别 Ctrl/Cmd+Z、Ctrl/Cmd+Shift+Z 和 Ctrl/Cmd+Y

- 快捷键监听改为 window capture 阶段，减少 Canvas/Konva 焦点或冒泡拦截导致的失效

- 兼容 event.code=KeyZ/KeyY，覆盖输入法或键盘布局下 event.key 不可靠的情况

- 保持输入框、文本域、下拉框和可编辑文本聚焦时不拦截撤销/重做

- 增加快捷键 helper 与 VideoWorkspace 回归测试，并更新需求、设计、测试计划和 AGENTS 文档

src/components/VideoWorkspace.test.tsx

@@ -141,6 +141,18 @@ describe('VideoWorkspace', () => {
     fireEvent.keyDown(window, { key: 'z', ctrlKey: true, shiftKey: true });
     expect(useStore.getState().masks).toEqual([mask]);
 
+    fireEvent.keyDown(window, { key: 'z', ctrlKey: true });
+    expect(useStore.getState().masks).toEqual([]);
+
+    fireEvent.keyDown(window, { key: 'y', ctrlKey: true });
+    expect(useStore.getState().masks).toEqual([mask]);
+
+    fireEvent.keyDown(window, { key: 'Process', code: 'KeyZ', ctrlKey: true });
+    expect(useStore.getState().masks).toEqual([]);
+
+    fireEvent.keyDown(window, { key: 'Process', code: 'KeyY', ctrlKey: true });
+    expect(useStore.getState().masks).toEqual([mask]);
+
     fireEvent.keyDown(screen.getByLabelText('传播起始帧'), { key: 'z', ctrlKey: true });
     expect(useStore.getState().masks).toEqual([mask]);
   });

src/components/VideoWorkspace.tsx

@@ -25,6 +25,7 @@ import { ModelStatusBadge } from './ModelStatusBadge';
 import { DEFAULT_AI_MODEL_ID, SAM2_MODEL_OPTIONS, type AiModelId, type Frame, type Mask, type Template, type TemplateClass } from '../store/useStore';
 import { cn } from '../lib/utils';
 import { normalizeClassMaskIds } from '../lib/maskIds';
+import { getUndoRedoShortcut } from '../lib/keyboardShortcuts';
 
 type PropagationDirection = 'forward' | 'backward';
 type PropagationProgress = {
@@ -521,26 +522,15 @@ export function VideoWorkspace({ onNavigateToAI }: { onNavigateToAI?: () => void
   );
   useEffect(() => {
     const handleWorkspaceShortcuts = (event: KeyboardEvent) => {
-      const target = event.target as HTMLElement | null;
-      const tagName = target?.tagName?.toLowerCase();
-      if (tagName === 'input' || tagName === 'textarea' || tagName === 'select' || target?.isContentEditable) return;
-      if (!event.metaKey && !event.ctrlKey) return;
-
-      const key = event.key.toLowerCase();
-      if (key === 'z') {
-        event.preventDefault();
-        if (event.shiftKey) redoMasks();
-        else undoMasks();
-        return;
-      }
-      if (key === 'y') {
-        event.preventDefault();
-        redoMasks();
-      }
+      const shortcut = getUndoRedoShortcut(event);
+      if (!shortcut) return;
+      event.preventDefault();
+      if (shortcut === 'undo') undoMasks();
+      else redoMasks();
     };
 
-    window.addEventListener('keydown', handleWorkspaceShortcuts);
-    return () => window.removeEventListener('keydown', handleWorkspaceShortcuts);
+    window.addEventListener('keydown', handleWorkspaceShortcuts, true);
+    return () => window.removeEventListener('keydown', handleWorkspaceShortcuts, true);
   }, [redoMasks, undoMasks]);
 
   const templates = useStore((state) => state.templates);

src/lib/keyboardShortcuts.test.ts

@@ -0,0 +1,32 @@
+import { describe, expect, it } from 'vitest';
+import { getUndoRedoShortcut, isEditableShortcutTarget } from './keyboardShortcuts';
+
+function keyboardEvent(init: KeyboardEventInit) {
+  return new KeyboardEvent('keydown', init);
+}
+
+describe('keyboardShortcuts', () => {
+  it('maps common undo and redo shortcuts', () => {
+    expect(getUndoRedoShortcut(keyboardEvent({ key: 'z', ctrlKey: true }))).toBe('undo');
+    expect(getUndoRedoShortcut(keyboardEvent({ key: 'Z', metaKey: true }))).toBe('undo');
+    expect(getUndoRedoShortcut(keyboardEvent({ key: 'z', ctrlKey: true, shiftKey: true }))).toBe('redo');
+    expect(getUndoRedoShortcut(keyboardEvent({ key: 'y', ctrlKey: true }))).toBe('redo');
+    expect(getUndoRedoShortcut(keyboardEvent({ key: 'Y', metaKey: true }))).toBe('redo');
+  });
+
+  it('falls back to physical key codes when key labels are unavailable', () => {
+    expect(getUndoRedoShortcut(keyboardEvent({ key: 'Process', code: 'KeyZ', ctrlKey: true }))).toBe('undo');
+    expect(getUndoRedoShortcut(keyboardEvent({ key: 'Process', code: 'KeyZ', ctrlKey: true, shiftKey: true }))).toBe('redo');
+    expect(getUndoRedoShortcut(keyboardEvent({ key: 'Process', code: 'KeyY', ctrlKey: true }))).toBe('redo');
+  });
+
+  it('ignores editable targets and alt-modified shortcuts', () => {
+    const input = document.createElement('input');
+    input.dispatchEvent(new Event('focus'));
+    expect(isEditableShortcutTarget(input)).toBe(true);
+    const event = keyboardEvent({ key: 'z', ctrlKey: true });
+    Object.defineProperty(event, 'target', { value: input });
+    expect(getUndoRedoShortcut(event)).toBeNull();
+    expect(getUndoRedoShortcut(keyboardEvent({ key: 'z', ctrlKey: true, altKey: true }))).toBeNull();
+  });
+});

src/lib/keyboardShortcuts.ts

@@ -0,0 +1,25 @@
+export type UndoRedoShortcut = 'undo' | 'redo';
+
+export function isEditableShortcutTarget(target: EventTarget | null): boolean {
+  if (!(target instanceof HTMLElement)) return false;
+  const tagName = target.tagName.toLowerCase();
+  return target.isContentEditable || tagName === 'input' || tagName === 'textarea' || tagName === 'select';
+}
+
+function isKey(event: KeyboardEvent, key: 'z' | 'y'): boolean {
+  return event.key.toLowerCase() === key || event.code === `Key${key.toUpperCase()}`;
+}
+
+export function getUndoRedoShortcut(event: KeyboardEvent): UndoRedoShortcut | null {
+  if (isEditableShortcutTarget(event.target)) return null;
+  if (!event.metaKey && !event.ctrlKey) return null;
+  if (event.altKey) return null;
+
+  if (isKey(event, 'z')) {
+    return event.shiftKey ? 'redo' : 'undo';
+  }
+  if (isKey(event, 'y')) {
+    return 'redo';
+  }
+  return null;
+}