chore(server): add ai document link on admin panel (#13428)

close AF-2766
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#### PR Dependency Tree


* **PR #13428** 👈

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**
* Configuration descriptions for the copilot plugin now include direct
links to relevant documentation for easier access to more information.

* **Style**
* Improved display of configuration descriptions to support and render
HTML content.

* **Refactor**
* The AI navigation item in the admin panel has been disabled and is no
longer visible.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/plugins/copilot/config.ts

@@ -42,7 +42,7 @@ declare global {
 
 defineModuleConfig('copilot', {
   enabled: {
-    desc: 'Whether to enable the copilot plugin.',
+    desc: 'Whether to enable the copilot plugin. <br> Document: <a href="https://docs.affine.pro/self-host-affine/administer/ai" target="_blank">https://docs.affine.pro/self-host-affine/administer/ai</a>',
     default: false,
   },
   scenarios: {