feat: "global-assets" placeholder

[wesleyboar]

Overview

Add a "Global-Assets" placeholder.

Related

• supported by feat: hide PluginImporter #42

Changes

• adds {% static_placeholder "global-assets" %}
• adds reorder_placeholders.css to move placeholder to bottom of editor's Structure list

Testing

1. Add to settings_custom.py:

   CMS_PLACEHOLDER_CONF = {
       'global-assets': {
           'plugins': ['SnippetPlugin'],
           'name': 'Global Assets (Styles & Scripts)',
       },
   }

2. Be logged in and edit page.
3. Open Structure panel.¹
4. ✅ Verify "Global Assets" placeholder is visible.
5. ✅ Verify "Global Assets" placeholder is at bottom.
6. Add plugin to "Global Assets".
7. ✅ Verify "Snippet" (and PluginImporter) is visible.
8. ✅ Add snippet. Save page. Refresh. Verify snippet is present on page.

UI

4 & 5	7	8	8

Notes

Warning

Reordering does not work if editor visits ?structure directly i.e. in a new window e.g. https://texascale.org/featured-stories/?structure.

Footnotes

1. Such that it opens in a sidebar, not in a new window. ↩