Visible and editable embedded notes

### 🚀 The feature, motivation and pitch

To have embedded notes (or sections of notes) embedded and available for editing from the main note. Then on saving the current buffer, the changes are written recursively to all embedded notes. This would make the editing experience truly superior than what is available in obsidian.
This is a challenging feature, though I think it is possible because of what is done by otter.nvim https://github.com/jmbuhr/otter.nvim. They embed parts of a code buffer into a quarto file which is available for editing.
I write papers by using embedded notes, so at least for me this would be very useful.

### Alternatives

_No response_

### Additional context

_No response_

Start by comparing obsidian.nvim's current note-embedding and save behavior with otter.nvim's buffer-embedding approach. Trace how the main buffer and embedded notes are represented; done means embedded sections can be edited in the main note and saving recursively persists changes to all embedded notes.

Written by the indexing model from the issue text.