[Genyus]

Content Editors and Reviewers can upload media but can't edit any attachment's title, alt text, caption or description, including files they uploaded themselves. One editor couldn't add source references to WebP images or correct the note on attachment 8325.

Cause

Core maps edit_post on an attachment to edit_posts for the uploader and to edit_others_posts for everyone else. Content Editors and Reviewers have upload_files and edit_courses, but neither of those.

Fix

A new mu-plugin, cbf-staff-media-details.php, adds a map_meta_cap filter. For users who have edit_courses but not edit_posts, it maps edit_post on any attachment that isn't in the trash to edit_courses. This covers the media modal (save-attachment), the attachment edit screen and POST /wp/v2/media/<id>. Deleting still follows core's rules.

Testing

Tested locally through the REST API on an attachment another user uploaded:

Request	Content Editor	Subscriber
POST /wp/v2/media/<id> with description and alt text	200, both saved	403
DELETE /wp/v2/media/<id>	403	403

Not yet checked in the media modal in a browser.

phpcs passes.

Correction to #1086

The testing table in #1086 overstated what had been checked at the time. Its single-pattern context=edit requests didn't actually send context, so they ran as view requests. I've now re-run them properly against develop. As a Content Editor, GET /wp/v2/blocks/5916?context=edit returns 200 with the raw content, and updating the pattern still returns 403. The fix works as described.