Independent OG metadata per page, with image data URIs

Every page in the admin app can now declare its own Open Graph title, description and image — independent of the document-level metadata. Previously the OG fields fell back to the document defaults if you did not set them explicitly, which meant sharing a deep link inside the admin produced a generic preview that did not match what the receiver was about to see.

Now you can configure OG metadata per page:

• Title — short, sharp, optimised for the share card not the browser tab.
• Description — two lines, sells the click.
• Image — embedded as a data URI in the page head, so the preview loads even if a CDN hop fails.

Result: shared deep links into the admin no longer feel anonymous.