- category content is the blogeditor type (uploadFolder categories): it is
stripped and reported like post content; the 422 CheckHTML gate is
retired and blank content still becomes NULL
- blogeditor and mlblogeditor Upload: magic-byte check for JPEG, PNG, GIF
and WebP matching the extension, safe lowercase names, storage through
classes.StoreMedia in the field's uploadFolder
- TestBlogEditorUploadSmoke, TestCategoriesAdminContent asserts the strip,
README describes the field types, admin saves and editor uploads