site coverPrefs as Ed option

[forresto]

coverPrefs defaults all three to allow (x !== false), but doesn't actually write the pref until the checkbox is un/selected.

Once we have sitewide coverPrefs, those could be an Ed option, so photographers don't feel like they have to uncheck boxes on every photo.

[forresto]

If #nofilter set site-wide, makes sense to show unchecked + disabled checkbox for allow filters. And note that filters are disabled site-wide.

Probably no demand for people to allow filters on specific blocks.

[forresto]

edit: dimmed read-only ones

[bergie]

One problem is that the post can be moved to another site

[forresto]

Then the app would mount it with the site defaults when opened there.

[forresto]

(@bergie I didn't see the problem.)

[forresto]

@bergie and does it block releasing the feature?

[nickvelloff]

Given the description of the solution, I don't see how moving them is a problem.