In-browser Slide Deck Editor?

### Description

Today I saw the amazing Slidev feature by @KermanX recently for being able to drag and drop elements and write changes to MDX:

> 🤏 In Slidev 0.49 (currently in beta), we will get draggable elements just like what you have in Keynote/PowerPoint!
>
> 🎩 What makes it even better is that the positions will be written back to your markdown file magically!

- Tweet with video: https://twitter.com/Slidevjs/status/1777886096124248241
- PR: https://github.com/slidevjs/slidev/pull/1402

In-browser slide deck editing capabilities would make authoring in Spectacle competitive with the user experience of PowerPoint or Keynote

This could include:

1. Draggable / resizeable / rotatable elements
2. Writing the changes back to the Markdown / MDX file
3. Editable text?

### Proposal

- Adding an "editing mode" in slide deck viewer
- Creating components for dragging, resizing and rotating elements
- Writing back to the `.md` or `.mdx` file on disk
- Probably more complex to allow for editing of elements within React components
- Maybe this can be implemented in a similar way to [Slidev's PR](https://github.com/slidevjs/slidev/pull/1402)?

### Alternatives Considered

1. Just use Slidev - problem: [Slidev doesn't support MDX / React](https://github.com/slidevjs/slidev/issues/372) ([reference 2](https://github.com/slidevjs/slidev/issues/273))

### Links / References

Already included above