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/__tests__/adapters/markdown.unit.spec.ts

@@ -3680,88 +3680,95 @@ bbb
     expect(nanoidReplacement(rawBlockSnapshot)).toEqual(blockSnapshot);
   });
 
-  test('inline latex', async () => {
-    const markdown = 'inline $E=mc^2$ latex\n';
-    const blockSnapshot: BlockSnapshot = {
-      type: 'block',
-      id: 'matchesReplaceMap[0]',
-      flavour: 'affine:note',
-      props: {
-        xywh: '[0,0,800,95]',
-        background: DefaultTheme.noteBackgrounColor,
-        index: 'a0',
-        hidden: false,
-        displayMode: NoteDisplayMode.DocAndEdgeless,
-      },
-      children: [
-        {
-          type: 'block',
-          id: 'matchesReplaceMap[1]',
-          flavour: 'affine:paragraph',
-          props: {
-            type: 'text',
-            text: {
-              '$blocksuite:internal:text$': true,
-              delta: [
-                {
-                  insert: 'inline ',
-                },
-                {
-                  insert: ' ',
-                  attributes: {
-                    latex: 'E=mc^2',
-                  },
-                },
-                {
-                  insert: ' latex',
-                },
-              ],
-            },
-          },
-          children: [],
+  describe('inline latex', () => {
+    test.each([
+      ['dollar sign syntax', 'inline $E=mc^2$ latex\n'],
+      ['backslash syntax', 'inline \\(E=mc^2\\) latex\n'],
+    ])('should convert %s correctly', async (_, markdown) => {
+      const blockSnapshot: BlockSnapshot = {
+        type: 'block',
+        id: 'matchesReplaceMap[0]',
+        flavour: 'affine:note',
+        props: {
+          xywh: '[0,0,800,95]',
+          background: DefaultTheme.noteBackgrounColor,
+          index: 'a0',
+          hidden: false,
+          displayMode: NoteDisplayMode.DocAndEdgeless,
         },
-      ],
-    };
+        children: [
+          {
+            type: 'block',
+            id: 'matchesReplaceMap[1]',
+            flavour: 'affine:paragraph',
+            props: {
+              type: 'text',
+              text: {
+                '$blocksuite:internal:text$': true,
+                delta: [
+                  {
+                    insert: 'inline ',
+                  },
+                  {
+                    insert: ' ',
+                    attributes: {
+                      latex: 'E=mc^2',
+                    },
+                  },
+                  {
+                    insert: ' latex',
+                  },
+                ],
+              },
+            },
+            children: [],
+          },
+        ],
+      };
 
-    const mdAdapter = new MarkdownAdapter(createJob(), provider);
-    const rawBlockSnapshot = await mdAdapter.toBlockSnapshot({
-      file: markdown,
+      const mdAdapter = new MarkdownAdapter(createJob(), provider);
+      const rawBlockSnapshot = await mdAdapter.toBlockSnapshot({
+        file: markdown,
+      });
+      expect(nanoidReplacement(rawBlockSnapshot)).toEqual(blockSnapshot);
     });
-    expect(nanoidReplacement(rawBlockSnapshot)).toEqual(blockSnapshot);
   });
 
-  test('latex block', async () => {
-    const markdown = '$$\nE=mc^2\n$$\n';
-
-    const blockSnapshot: BlockSnapshot = {
-      type: 'block',
-      id: 'matchesReplaceMap[0]',
-      flavour: 'affine:note',
-      props: {
-        xywh: '[0,0,800,95]',
-        background: DefaultTheme.noteBackgrounColor,
-        index: 'a0',
-        hidden: false,
-        displayMode: NoteDisplayMode.DocAndEdgeless,
-      },
-      children: [
-        {
-          type: 'block',
-          id: 'matchesReplaceMap[1]',
-          flavour: 'affine:latex',
-          props: {
-            latex: 'E=mc^2',
-          },
-          children: [],
+  describe('latex block', () => {
+    test.each([
+      ['dollar sign syntax', '$$\nE=mc^2\n$$\n'],
+      ['backslash syntax', '\\[\nE=mc^2\n\\]\n'],
+    ])('should convert %s correctly', async (_, markdown) => {
+      const blockSnapshot: BlockSnapshot = {
+        type: 'block',
+        id: 'matchesReplaceMap[0]',
+        flavour: 'affine:note',
+        props: {
+          xywh: '[0,0,800,95]',
+          background: DefaultTheme.noteBackgrounColor,
+          index: 'a0',
+          hidden: false,
+          displayMode: NoteDisplayMode.DocAndEdgeless,
         },
-      ],
-    };
+        children: [
+          {
+            type: 'block',
+            id: 'matchesReplaceMap[1]',
+            flavour: 'affine:latex',
+            props: {
+              latex: 'E=mc^2',
+            },
+            children: [],
+          },
+        ],
+      };
 
-    const mdAdapter = new MarkdownAdapter(createJob(), provider);
-    const rawBlockSnapshot = await mdAdapter.toBlockSnapshot({
-      file: markdown,
+      const mdAdapter = new MarkdownAdapter(createJob(), provider);
+      const rawBlockSnapshot = await mdAdapter.toBlockSnapshot({
+        file: markdown,
+      });
+      expect(nanoidReplacement(rawBlockSnapshot)).toEqual(blockSnapshot);
     });
-    expect(nanoidReplacement(rawBlockSnapshot)).toEqual(blockSnapshot);
   });
 
   test('reference', async () => {

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,
+];