Accessibility/QoL: Read-only checkboxes in Dendron Preview

[not-so-smart]

Please select if your request is either something new or an enhancement

• Enhancement of an existing Feature.
• Request of a new feature.

Please select the area your request applies to. (Multiple selections are Possible. You can leave blank if you're not sure.)

• Workspace - VSCode workspace, vaults, Intellisense/autocomplete, Dendron settings
• Lookup - Dendron's Lookup Command
• Views - Dendron Preview, Tree View, Side Panels in the UI
• Schema - Dendron Schemas
• Pod - Data import from / export to Dendron
• Publish - External Site Publish
• Markdown - Markdown features, such as syntax support and features

Is your feature request related to a problem? Please describe

Because checkboxes are greyed/read-only in the preview pane, you have to check off items using markdown which is inconvenient. Additionally, the greyed boxes make it difficult to distinguish checked from unchecked items.

Describe the solution you'd like

Editable checkboxes in the preview pane would be nice. Clicking a checkbox would put an [x] in the corresponding markdown.

Describe alternatives you've considered

For the visibility/accessibility issue: Some other way (with themes perhaps?) to make read-only checkboxes more visible and distinguishable from their unchecked counterparts

For the convenience/qol issue: An option in the editor, via the right-click menu or lightbulb tips, when focused on a checklist item, to toggle between check/uncheck

Additional context

Read-only checkboxes in the Dendron editor:

[ScriptAutomate]

Related: #1571