feat(mobile): mobile at menu (#8727)

Close [BS-1608](https://linear.app/affine-design/issue/BS-1608/mobile-menu), related PR: https://github.com/toeverything/blocksuite/pull/8681

packages/common/infra/src/modules/feature-flag/constant.ts

@@ -162,6 +162,14 @@ export const AFFINE_FLAGS = {
     configurable: false,
     defaultState: isMobile,
   },
+  enable_mobile_linked_doc_menu: {
+    category: 'blocksuite',
+    bsFlag: 'enable_mobile_linked_doc_menu',
+    displayName: 'Mobile Linked Doc Widget',
+    description: 'Enables the mobile linked doc menu.',
+    configurable: false,
+    defaultState: isMobile,
+  },
   enable_snapshot_import_export: {
     category: 'affine',
     displayName: 'Enable Snapshot Import Export',

packages/frontend/core/src/components/blocksuite/block-suite-editor/specs/custom/widgets/linked.ts

@@ -4,7 +4,10 @@ import { JournalService } from '@affine/core/modules/journal';
 import { I18n } from '@affine/i18n';
 import { track } from '@affine/track';
 import type { EditorHost } from '@blocksuite/affine/block-std';
-import type { AffineInlineEditor } from '@blocksuite/affine/blocks';
+import type {
+  AffineInlineEditor,
+  LinkedWidgetConfig,
+} from '@blocksuite/affine/blocks';
 import { LinkedWidgetUtils } from '@blocksuite/affine/blocks';
 import type { DocMeta } from '@blocksuite/affine/store';
 import { type FrameworkProvider, WorkspaceService } from '@toeverything/infra';
@@ -74,7 +77,7 @@ function createNewDocMenuGroup(
 // TODO: fix the type
 export function createLinkedWidgetConfig(
   framework: FrameworkProvider
-): Partial<Record<string, unknown>> {
+): Partial<LinkedWidgetConfig> {
   return {
     getMenus: (
       query: string,
@@ -142,6 +145,17 @@ export function createLinkedWidgetConfig(
         ),
       ]);
     },
+    mobile: {
+      useScreenHeight: BUILD_CONFIG.isIOS,
+      scrollContainer: window,
+      scrollTopOffset: () => {
+        const header = document.querySelector('header');
+        if (!header) return 0;
+
+        const { y, height } = header.getBoundingClientRect();
+        return y + height;
+      },
+    },
   };
 }