Add an "opt-in" mode per page (e.g. for Themers)

After thinking about this, I think a setting like this might be most helpful:

Run Editoria11y check on:

• Page load (default)
• Widget click

This setting allows running Editoria11y check on page load or when the user needs it, to prevent unwanted DOM manipulation.

Or add a Editoria11y per-user (cookie / local storage) setting to enable / disable Editoria11y auto-check on page load

Hmm....unless there is a bug, if "Show tips automatically when issues are detected" is set to anything other than "Assertive" (the default), it will only auto-draw the tips if there are new errors on the page. Themers repeatedly refreshing a page should only have stuff tossed all over their work once if they close the toggle and refresh. Subsequent loads will read their local preference for "shut," see that the number of issues hasn't changed, and start minimized (e.g., as an on-demand check). Maybe try setting that to "On first detection" or "Polite" during development and see if that satisfies your themers? "On first detection" used to be the default, but too many editors were ignoring the toggle...

I would consider a merge request to add a per-user preference for "Show tips automatically when issues are detected."