refactor(infra): remove old plugin system (#5411)

plugin system need redesign

README.md

@@ -113,20 +113,6 @@ If you have questions, you are welcome to contact us. One of the best places to
 | [@toeverything/y-indexeddb](packages/common/y-indexeddb) | IndexedDB database adapter for Yjs | [![](https://img.shields.io/npm/dm/@toeverything/y-indexeddb?style=flat-square&color=eee)](https://www.npmjs.com/package/@toeverything/y-indexeddb) |
 | [@toeverything/theme](packages/common/theme)             | AFFiNE theme                       | [![](https://img.shields.io/npm/dm/@toeverything/theme?style=flat-square&color=eee)](https://www.npmjs.com/package/@toeverything/theme)             |
 
-## Plugins
-
-> Plugins are a way to extend the functionality of AFFiNE. You can use plugins to add new blocks, new features, and even new ways to edit content.
->
-> (Currently, the plugin system is under heavy development. You will see the plugin system in the canary release.)
-
-- [@affine/sdk](./packages/common/sdk) - SDK for developing plugins
-- [@affine/plugin-cli](./tools/plugin-cli) - CLI for developing plugins
-
-| Official Plugin                                                  | Description                               | Status |
-| ---------------------------------------------------------------- | ----------------------------------------- | ------ |
-| [@affine/copilot-plugin](./packages/plugins/copilot)             | AI Copilot that help you document writing | 🚧     |
-| [@affine/image-preview-plugin](./packages/plugins/image-preview) | Component for previewing an image         | ✅     |
-
 ## Upstreams
 
 We would also like to give thanks to open-source projects that make AFFiNE possible: