修复画布美术Agent规划与附件弹窗

显式标记待确认工具并在规划完成后结束当前回合
保留普通工具和Hook跳过场景的最大轮次保护并补充回归测试
修复附件选择弹窗Portal主题丢失导致的透明背景
同步画布Agent专题文档与共享排障经验

src/components/image-editor/EditorAgentConversation/EditorAgentConversationPanelView.test.tsx

@@ -268,6 +268,10 @@ describe('EditorAgentConversationPanelView', () => {
     const attachmentDialog = screen.getByRole('dialog', {
       name: '选择图片附件',
     });
+    expect(attachmentDialog.parentElement?.className).toContain(
+      'platform-theme--light',
+    );
+    expect(attachmentDialog.className).toContain('platform-remap-surface');
     expect(
       within(attachmentDialog).queryByRole('checkbox', {
         name: '选择画布图片 未入库图层',

src/components/image-editor/EditorAgentConversation/EditorAgentConversationPanelView.tsx

@@ -23,7 +23,7 @@ import {
 } from '@/packages/shared/src/contracts';
 import { PlatformActionButton } from '@/src/components/common/PlatformActionButton.tsx';
 import { PlatformDangerConfirmDialog } from '@/src/components/common/PlatformDangerConfirmDialog.tsx';
-import { UnifiedModal } from '@/src/components/common/UnifiedModal.tsx';
+import { PlatformToolModalShell } from '@/src/components/common/PlatformToolModalShell.tsx';
 import AttachmentChip from '@/src/components/image-editor/EditorAgentConversation/AttachmentChip.tsx';
 import { attachmentKey } from '@/src/components/image-editor/EditorAgentConversation/common.ts';
 import {
@@ -150,7 +150,7 @@ function AttachmentPickerModal({
   const visibleOptions = tab === 'canvas' ? canvasOptions : libraryOptions;
 
   return (
-    <UnifiedModal
+    <PlatformToolModalShell
       open={open}
       title="选择图片附件"
       size="md"
@@ -228,7 +228,7 @@ function AttachmentPickerModal({
           })}
         </div>
       </div>
-    </UnifiedModal>
+    </PlatformToolModalShell>
   );
 }