feat(server): improve markdown parse (#14580)

#### PR Dependency Tree


* **PR #14580** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

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

* **New Features**
* Markdown conversion now reports lists of known-unsupported and unknown
block identifiers encountered during parsing, and separates them from
the main markdown output.

* **Bug Fixes**
  * Improved error handling and logging around markdown parsing.

* **Tests**
* Updated tests and snapshots to reflect the new block-list fields and
the adjusted markdown output.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/__tests__/e2e/doc-service/__snapshots__/controller.spec.ts.md

@@ -9,6 +9,16 @@ Generated by [AVA](https://avajs.dev).
 > Snapshot 1
 
     {
+      knownUnsupportedBlocks: [
+        'RX4CG2zsBk:affine:note',
+        'S1mkc8zUoU:affine:note',
+        'yGlBdshAqN:affine:note',
+        '6lDiuDqZGL:affine:note',
+        'cauvaHOQmh:affine:note',
+        '2jwCeO8Yot:affine:note',
+        'c9MF_JiRgx:affine:note',
+        '6x7ALjUDjj:affine:surface',
+      ],
       markdown: `AFFiNE is an open source all in one workspace, an operating system for all the building blocks of your team wiki, knowledge management and digital assets and a better alternative to Notion and Miro.␊
       ␊
       ␊
@@ -70,35 +80,9 @@ Generated by [AVA](https://avajs.dev).
       ␊
       ␊
       ␊
-      ␊
-      [](Bookmark,https://affine.pro/)␊
-      ␊
-      ␊
-      [](Bookmark,https://www.youtube.com/@affinepro)␊
-      ␊
-      <img␊
-        src="blob://BFZk3c2ERp-sliRvA7MQ_p3NdkdCLt2Ze0DQ9i21dpA="␊
-        alt=""␊
-        width="1302"␊
-        height="728"␊
-      />␊
-      ␊
-      <img␊
-        src="blob://HWvCItS78DzPGbwcuaGcfkpVDUvL98IvH5SIK8-AcL8="␊
-        alt=""␊
-        width="1463"␊
-        height="374"␊
-      />␊
-      ␊
-      <img␊
-        src="blob://ZRKpsBoC88qEMmeiXKXqywfA1rLvWoLa5rpEh9x9Oj0="␊
-        alt=""␊
-        width="862"␊
-        height="1388"␊
-      />␊
-      ␊
       `,
       title: 'Write, Draw, Plan all at Once.',
+      unknownBlocks: [],
     }
 
 ## should get doc markdown return null when doc not exists