Refactor user and global info stores to shared package (#7858)

#### What type of PR is this?

/area ui
/kind feature
/milestone 2.22.x

#### What this PR does / why we need it:

This PR moves the `currentUser` and `globalInfo` stores to the `@halo-dev/console-shared` package, making them easily accessible for plugins.

In addition, it’s now possible for plugins to define their own global stores using Pinia.

#### Does this PR introduce a user-facing change?

```release-note
- 在 `@halo-dev/console-shared` 包中提供 `stores` 对象，包含 currentUser 和 globalInfo。
- 支持在插件的 UI 中使用 Pinia 定义全局 Store
```

ui/packages/shared/src/index.ts

@@ -11,6 +11,7 @@ export * from "./states/plugin-installation-tabs";
 export * from "./states/plugin-tab";
 export * from "./states/theme-list-tabs";
 export * from "./states/user-tab";
+export * from "./stores";
 export * from "./types/menus";
 export * from "./types/plugin";
 export * from "./types/widget";