Add WYSIWYG markdown editor option

[neopostmodern]

Current best option: tiptap + mui-tiptap + tiptap-markdown

Issues / regressions:

• [x] multiline table cells
  • was in principle fixed in 0.8.3 (for paragraphs) – but converts entire table to HTML
  • broken for hardbreaks
  • fixed in 0.8.9

• [x] nested lists

  • in general nested lists work
  • but you can't add sub-items to checklist entries / increase indent
  • nested check-lists work in an online demo – but not e.g. bullet lists as children of check-lists – might be related to mui-tiptap?
  • [ ] default to line breaks, not paragraph breaks
  • [x] or maybe don't? if the behavior is consistent and understandable, standard break/hardbreak behavior might nice and consistent with regular markdown (also saves a lot of work to adapt tiptap)
  • [x] need a migration though to convert implicit to explicit hardbreaks (and to convert double-line-breaks to paragraphs...)
  • [ ] hard-break button on mobile
  • [x] styling:
    • [x] inline code
    • [x] nested check lists
    • [x] invisible bullet points when nested in check list
    • [x] list positioning
  • [ ] Bullet list issues
  • [ ] disable + as list symbol?
  • [ ] preserve escaped lists (see https://github.com/aguingand/tiptap-markdown/issues/65)
  • [ ] Font sizes and spacing

  Trying to write some tests for these scenarios

  Regressions:

  • No intuitive hard breaks on mobile?
  • No easy mixing of check-lists and other lists (see https://github.com/ueberdosis/tiptap/issues/166, https://github.com/ueberdosis/tiptap/issues/2428)

[neopostmodern]

Sandbox to test mui-tiptap without tiptap-markdown to isolate issues: https://codesandbox.io/p/devbox/mui-tiptap-demo-3zl2l6?file=%2Fsrc%2FEditor.tsx Sandbox with mui-tiptap and tiptap-markdown: https://codesandbox.io/p/devbox/mui-tiptap-demo-forked-nxv9m2