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/plain-text/delta-converter.ts

@@ -5,12 +5,12 @@ import {
 import type { DeltaInsert, ExtensionType } from '@blocksuite/store';
 
 import type { AffineTextAttributes } from '../../types/index.js';
+import type { TextBuffer } from '../types/adapter.js';
 import {
   type ASTToDeltaMatcher,
   DeltaASTConverter,
   type InlineDeltaMatcher,
-  type TextBuffer,
-} from '../types/adapter.js';
+} from '../types/delta-converter.js';
 
 export type InlineDeltaToPlainTextAdapterMatcher =
   InlineDeltaMatcher<TextBuffer>;