refactor(editor): extract mobile extension builder (#12239)

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **New Features**
  - Introduced a new mobile view extension that activates mobile-specific UI features based on the runtime environment.
  - Automatically enables mobile keyboard toolbar and linked document menu features in mobile contexts.

- **Improvements**
  - Simplified code and paragraph block configurations on mobile, including disabling line numbers and adjusting placeholders.
  - Enhanced configuration chaining to include mobile-specific settings by default.
  - Improved extension registration flow with method chaining support.

- **Refactor**
  - Removed deprecated mobile patch classes and configurations, consolidating mobile logic into dedicated extensions.
  - Streamlined mobile-related code for better maintainability and performance.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/blocks/code/src/view.ts

@@ -11,6 +11,7 @@ import {
 import { literal, unsafeStatic } from 'lit/static-html.js';
 
 import { getCodeClipboardExtensions } from './clipboard/index.js';
+import { CodeBlockConfigExtension } from './code-block-config';
 import {
   CodeBlockInlineManagerExtension,
   CodeBlockUnitSpecExtension,
@@ -21,7 +22,7 @@ import { AFFINE_CODE_TOOLBAR_WIDGET } from './code-toolbar/index.js';
 import { codeSlashMenuConfig } from './configs/slash-menu.js';
 import { effects } from './effects.js';
 
-export const codeToolbarWidget = WidgetViewExtension(
+const codeToolbarWidget = WidgetViewExtension(
   'affine:code',
   AFFINE_CODE_TOOLBAR_WIDGET,
   literal`${unsafeStatic(AFFINE_CODE_TOOLBAR_WIDGET)}`
@@ -51,6 +52,12 @@ export class CodeBlockViewExtension extends ViewExtensionProvider {
     ]);
     if (!this.isMobile(context.scope)) {
       context.register(codeToolbarWidget);
+    } else {
+      context.register(
+        CodeBlockConfigExtension({
+          showLineNumbers: false,
+        })
+      );
     }
   }
 }