feat(core): markdown-diff & patch apply (#12844)

## New Features
- **Markdown diff**: 
- Introduced block-level diffing for markdown content, enabling
detection of insertions, deletions, and replacements between document
versions.
  - Generate patch operations from markdown diff.
- **Patch Renderer**: Transfer patch operations to a render diff which
can be rendered into page body.
- **Patch apply**：Added functionality to apply patch operations to
documents, supporting block insertion, deletion, and content
replacement.

## Refactors
* Move `affine/shared/__tests__/utils` to
`blocksuite/affine-shared/test-utils`


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

* **New Features**
* Introduced utilities for declarative creation and testing of document
structures using template literals.
* Added new functions and types for block-level markdown diffing and
patch application.
* Provided a utility to generate structured render diffs for markdown
blocks.
* Added a unified test-utils entry point for easier access to testing
helpers.

* **Bug Fixes**
* Updated import paths in test files to use the new test-utils location.

* **Documentation**
* Improved example usage in documentation to reflect the new import
paths for test utilities.

* **Tests**
* Added comprehensive test suites for markdown diffing, patch
application, and render diff utilities.

* **Chores**
* Updated package dependencies and export maps to expose new test
utilities.
* Refactored internal test utilities organization for clarity and
maintainability.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

> CLOSE AI-271 AI-272 AI-273

blocksuite/affine/shared/src/test-utils/README.md

@@ -0,0 +1,79 @@
+# AFFiNE Test Tools
+
+## Structured Document Creation
+
+`affine-template.ts` provides a concise way to create test documents, using a html-like syntax.
+
+### Basic Usage
+
+```typescript
+import { affine } from '@blocksuite/affine-shared/test-utils';
+
+// Create a simple document
+const doc = affine`
+  <affine-page>
+    <affine-note>
+      <affine-paragraph>Hello, World!</affine-paragraph>
+    </affine-note>
+  </affine-page>
+`;
+```
+
+### Complex Structure Example
+
+```typescript
+// Create a document with multiple notes and paragraphs
+const doc = affine`
+  <affine-page title="My Test Page">
+    <affine-note>
+      <affine-paragraph>First paragraph</affine-paragraph>
+      <affine-paragraph>Second paragraph</affine-paragraph>
+    </affine-note>
+    <affine-note>
+      <affine-paragraph>Another note</affine-paragraph>
+    </affine-note>
+  </affine-page>
+`;
+```
+
+### Application in Tests
+
+This tool is particularly suitable for creating documents with specific structures in test cases:
+
+```typescript
+import { describe, expect, it } from 'vitest';
+import { affine } from '../__tests__/utils/affine-template';
+
+describe('My Test', () => {
+  it('should correctly handle document structure', () => {
+    const doc = affine`
+      <affine-page>
+        <affine-note>
+          <affine-paragraph>Test content</affine-paragraph>
+        </affine-note>
+      </affine-page>
+    `;
+
+    // Get blocks
+    const pages = doc.getBlocksByFlavour('affine:page');
+    const notes = doc.getBlocksByFlavour('affine:note');
+    const paragraphs = doc.getBlocksByFlavour('affine:paragraph');
+
+    expect(pages.length).toBe(1);
+    expect(notes.length).toBe(1);
+    expect(paragraphs.length).toBe(1);
+
+    // Perform more tests here...
+  });
+});
+```
+
+### Supported Block Types
+
+Currently supports the following block types:
+
+- `affine-page` → `affine:page`
+- `affine-note` → `affine:note`
+- `affine-paragraph` → `affine:paragraph`
+- `affine-list` → `affine:list`
+- `affine-image` → `affine:image`