feat(core): support ai doc search panel (#9831)

Support issue [BS-2351](https://linear.app/affine-design/issue/BS-2351) and [BS-2461](https://linear.app/affine-design/issue/BS-2461).

## What changed?
- Add `chat-panel-add-popover` component.
- Refactor part of `AtMenuConfigService` into `DocSearchMenuService`.
- Add signal `content` property to `DocChip` interface for markdown content update.

<div class='graphite__hidden'>
          <div>🎥 Video uploaded on Graphite:</div>
            <a href="https://app.graphite.dev/media/video/sJGviKxfE3Ap685cl5bj/ff1d69b3-edd6-4d33-a01d-8b16e5192af7.mov">
              <img src="https://app.graphite.dev/api/v1/graphite/video/thumbnail/sJGviKxfE3Ap685cl5bj/ff1d69b3-edd6-4d33-a01d-8b16e5192af7.mov">
            </a>
          </div>
<video src="https://graphite-user-uploaded-assets-prod.s3.amazonaws.com/sJGviKxfE3Ap685cl5bj/ff1d69b3-edd6-4d33-a01d-8b16e5192af7.mov">录屏2025-01-21 18.46.29.mov</video>

packages/frontend/core/src/modules/index.ts

@@ -16,6 +16,7 @@ import { configureDocModule } from './doc';
 import { configureDocDisplayMetaModule } from './doc-display-meta';
 import { configureDocInfoModule } from './doc-info';
 import { configureDocLinksModule } from './doc-link';
+import { configDocSearchMenuModule } from './doc-search-menu';
 import { configureDocsSearchModule } from './docs-search';
 import { configureEditorModule } from './editor';
 import { configureEditorSettingModule } from './editor-setting';
@@ -91,6 +92,7 @@ export function configureCommonModules(framework: Framework) {
   configureDocInfoModule(framework);
   configureOpenInApp(framework);
   configAtMenuConfigModule(framework);
+  configDocSearchMenuModule(framework);
   configureDndModule(framework);
   configureCommonGlobalStorageImpls(framework);
   configureAINetworkSearchModule(framework);