closes https://github.com/TryGhost/Team/issues/1013
Image cards could be dropped into a gallery when at least one image was already present but there was no handling for image cards being dropped onto an empty gallery.
- added `data-gallery` attribute to the placeholder element so it gets picked up by the drag-and-drop container registration
- added drag enter/leave event handlers so we can show the same dropzone indicator as when a standard file is being dropped onto an empty gallery
- updated the drop handling to handle insertion when no images already exist by forcing insertion at index `0`
- updated the register or refresh handler to switch between different drag-and-drop container elements as needed and switched to `scheduleOnce` to prevent duplicate containers being created if the function is called twice before render occurs
no issue
- show the toolbar icon for any `<KoenigCard>` instance that has the `saveAsSnippet` action passed to it
- currently that's all cards except the HR card because that's a primitive element rather than containing any user-defined content
- add `koenigUi.inputHasFocus` so that card toolbars can be hidden when the snippet input is displayed
no issue
Keeps component JS backing files and template files in the same directory which avoids hunting across directories when working with components. Also lets you see all components when looking at one directory, whereas previously template-only or js-only components may not have been obvious without looking at both directories.
- ran [codemod](https://github.com/ember-codemods/ember-component-template-colocation-migrator/) for app-level components
- manually moved in-repo-addon component templates in `lib/koenig-editor`
- removed all explicit `layout` imports as JS/template associations are now made at build-time removing the need for them
- updated `.embercli` to default to new flat component structure
