Unified API for VitePress Plugins

Is your feature request related to a problem? Please describe.

The VitePress community has develop a range of amazing plugins which elevate the user experience of VitePress to another level.

Unfortunately, there isn't a clear and unified way of how users add these plugins to their VitePress setup. For example

Sometime we have to add options to markdown and the Theme enhanceApp https://vitepress-plugins.sapphi.red/tabs/#usage
Sometimes we have to register plugins to the underlying Vite instance https://github.com/ATQQ/sugar-blog/tree/master/packages/vitepress-plugin-pagefind#usage
Sometimes a wrapper is provided https://emersonbottero.github.io/vitepress-plugin-mermaid/guide/getting-started.html#setup-it-up to wrap the entire defineConfig object
Sometimes a wrapper is provided https://vvp.imb11.dev/guide/basic-setup#configuration-setup that replaces the defineConfig object

I understand the reason for why these different approaches are required, as different plugins might interact with different components of the VitePress stack (underlying architecture, markdown rendering, frontend Vue components...).

However, for a user this can be very confusing. Furthermore, if more plugins would start to adapt the wrapper way, we would quickly end up in a world where a config.ts starts like this:

export default withMermaid({withPageFind({withTabs({...

Which I (personally) find really hard to read and maintain.

Describe the solution you'd like

It would be great to have a common "API" for Vite Press plugins? I.e. providing hooks for all that required, underlying components for plugins to hook into (plugin developers would have a much better understand how requirements could look like). Once this is available, it would also be great to have a "suggested" plugin development guide.

Describe alternatives you've considered

There isn't really a good alternative, other than the way it is right now. It's the plugin developers responsibility to determine which of the above way they would choose for their plugin. Which puts an additional overhead on the developer potentially discouraging the development of new, great plugins.

Additional context

I'm not a plugin developer myself, so this issue was created from a user's PoV. However, there was a quick chat on Discord about this topic, where plugin developer also confirmed that this would be a nice addition to have.

Validations

[X] Follow our Code of Conduct
[X] Read the docs.
[X] Read the Contributing Guidelines.
[X] Check that there isn't already an issue that asks for the same feature to avoid creating a duplicate.

Probably time will tell that a great approach to solve this issue is to bring VitePress closer to Vite. Vite 5.3 released a more unified API for plugins, and Vite 6 is going to improve it. Vite's environment API enables plugins and projects that build on top of Vite to work together. One great benefit is: these plugins will not need anymore to adapt themselves to different environments. This is all going to be dealt by Vite. For example, a plugin needs SSR environment? Needs Mermaid or another sort of wrapper? This is more or less what Vite is making it easier to deal with from now on. Unified API for VitePress may be an easier challenge when taking into consideration Vite's unified API, in order to avoid duplicating this kind of effort.

vuejs / vitepress