feat(editor): support markdown adapter preprocessed with latex delimiters (#11431)

To close [BS-2870](https://linear.app/affine-design/issue/BS-2870/支持识别-和-[-包裹内容为公式)

## Add Markdown Preprocessor Extension and Enhanced LaTeX Support

### Markdown Preprocessor Extension
This PR introduces a new preprocessor extension for Markdown adapters that allows preprocessing of content before conversion:

Adds a new PreprocessorManager for handling text transformations
Introduces extensible preprocessor interface that supports different processing levels (block/slice/doc)

Integrates preprocessor extension into the existing Markdown adapter workflow

### LaTeX Support Enhancement
Extends LaTeX support to handle both traditional and alternative syntax:
Adds support for backslash LaTeX syntax:

Block math: ```\[...\] ``` alongside existing ```$$...$$```
Inline math: ```\(...\) ``` alongside existing ```$...$```

Implements LaTeX preprocessor to standardize syntax before conversion

Updates tests to cover both syntax variants

blocksuite/affine/all/src/adapters/extension.ts

@@ -20,6 +20,7 @@ import type { ExtensionType } from '@blocksuite/store';
 
 import { defaultBlockHtmlAdapterMatchers } from './html/block-matcher';
 import { defaultBlockMarkdownAdapterMatchers } from './markdown/block-matcher';
+import { defaultMarkdownPreprocessors } from './markdown/preprocessor';
 import { defaultBlockNotionHtmlAdapterMatchers } from './notion-html/block-matcher';
 import { defaultBlockPlainTextAdapterMatchers } from './plain-text/block-matcher';
 
@@ -44,6 +45,7 @@ export const MarkdownAdapterExtension: ExtensionType[] = [
   ...MarkdownInlineToDeltaAdapterExtensions,
   ...defaultBlockMarkdownAdapterMatchers,
   ...InlineDeltaToMarkdownAdapterExtensions,
+  ...defaultMarkdownPreprocessors,
 ];
 
 export const NotionHtmlAdapterExtension: ExtensionType[] = [

blocksuite/affine/all/src/adapters/index.ts

@@ -1,5 +1,6 @@
 export * from './extension.js';
 export * from './html/block-matcher.js';
 export * from './markdown/block-matcher.js';
+export * from './markdown/preprocessor.js';
 export * from './notion-html/block-matcher.js';
 export * from './plain-text/block-matcher.js';

blocksuite/affine/all/src/adapters/markdown/preprocessor.ts

@@ -0,0 +1,7 @@
+import { CodeMarkdownPreprocessorExtension } from '@blocksuite/affine-block-code';
+import { LatexMarkdownPreprocessorExtension } from '@blocksuite/affine-block-latex';
+
+export const defaultMarkdownPreprocessors = [
+  LatexMarkdownPreprocessorExtension,
+  CodeMarkdownPreprocessorExtension,
+];