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/shared/src/adapters/index.ts

@@ -30,11 +30,14 @@ export {
   MarkdownAdapter,
   MarkdownAdapterFactoryExtension,
   MarkdownAdapterFactoryIdentifier,
+  type MarkdownAdapterPreprocessor,
   type MarkdownAST,
   MarkdownASTToDeltaExtension,
   type MarkdownASTToDeltaMatcher,
   MarkdownASTToDeltaMatcherIdentifier,
   MarkdownDeltaConverter,
+  MarkdownPreprocessorExtension,
+  MarkdownPreprocessorManager,
 } from './markdown';
 export * from './middlewares';
 export * from './mix-text';