182a2225 Added the Facebook card pane to the React editor's settings sidebar
no ref
The React editor's settings sidebar had a slot for the Facebook card but
nothing in it, so the post's Open Graph image, title and description could
only be edited from the Ember post settings menu.
The pane is the Ember subview's behaviour: an image uploaded through the
same hook the feature image uses and committed as it lands, a title and
description staged as the writer types and committed on the blur that ends
the edit, and the card those three produce previewed underneath. Committing
is not saving, so the sidebar's own policy still decides whether a value is
persisted or staged. Each line falls back rather than emptying — the title
through the meta title to the post's own, the description through the post's
excerpt, meta description and generated excerpt to the site's, the image
through the feature image to the site's social and cover images — and those
fallbacks are what the inputs show as placeholders. The two column widths
are enforced where the writer is typing and refuse the save they would
otherwise fail, so the validator gate the sidebar already runs gains the two
Open Graph rules in the post validator's own order. Every role that can open
the panel can open the pane, as in Ember.
The site facts the card falls back to are read off the editor's card config
rather than a second settings request, which puts the site's Open Graph,
Twitter and cover images beside the site description the config already
carried. The keys the validator reads are now a list the prepared save is
derived from, so a field added to the validator is carried without editing
the save path as well.