feat: init new plugin system (#3323)

packages/plugin-infra/src/entry.ts

@@ -0,0 +1,17 @@
+import type { EditorContainer } from '@blocksuite/editor';
+import type { FC } from 'react';
+
+export type Part = 'headerItem' | 'editor' | 'window';
+
+export type CallbackMap = {
+  headerItem: (root: HTMLElement) => () => void;
+  window: (root: HTMLElement) => () => void;
+  editor: (root: HTMLElement, editor: EditorContainer) => () => void;
+};
+
+export interface PluginContext {
+  register: <T extends Part>(part: T, callback: CallbackMap[T]) => void;
+  utils: {
+    PluginProvider: FC;
+  };
+}