[Feature]: A shortcut to toggle sidebar visibility

[Sepush]

What problem does this feature solve?

I want a shortcut to toggle sidebar visibility
I know we can use search query sidebar=0 to toggle
A short cut could provides a better user experience

I did some prototype in #2142 but still have a lot detail to discuss

What does the proposed API look like?

• If we need a config flag to opt-in looks like

export default defineConfig({
  themeConfig: {
    sidebar: {
      collapsible:true,// as default
      ...otherConfig,
    },
  },
});

• current I use lucide:panel-left-close and lucide:panel-left-open as toggle logo (if any logo prefer I will replace them)
• any design or interactive need update?
• demo preview
  https://github.com/user-attachments/assets/6dd06fad-429f-4ff7-8695-3d4feee2d8f9

[JounQin]

collapsible could also mean y-order expanding/collapsing.

[Sepush]

collapsible could also mean y-order expanding/collapsing.

sidebar.collapsed collapsed or collapsible prop is a common to control the whole sider

the y-order is control by sidebar.path.collapsible

comment if there is a better naming

// current
interface SidebarGroup {
  text: string;
  link?: string;
  items: SidebarItem[];
  // whether to be collapsible
  collapsible?: boolean;
  // Whether to be collapsed by default
  collapsed?: boolean;
  // svg tag string or image URL(optional)
  tag?: string;
}

export interface Sidebar  {
  [path: string]: (
    | SidebarGroup
    | SidebarItem
    | SidebarDivider
    | SidebarSectionHeader
  )[];
}
// after
export interface SidebarBase {
  collapsible?: boolean;
}

export type Sidebar = SidebarBase & {
  [path: string]: (
    | SidebarGroup
    | SidebarItem
    | SidebarDivider
    | SidebarSectionHeader
  )[];
};

then user config could be

const sidebar: Sidebar = {
  collapsible: true,
  "/docs": [
    collapsible:true,
    { type: "sectionHeader", title: "Introduction" },
    { type: "item", text: "Getting Started", link: "/start" },
    { type: "divider" },
    // ... more items
  ],
  "/api": [
    // different configuration for API section
  ]
};

[JounQin]

I'm saying these two options naming could be confusing.