Pure s-expression block editor replacing React/Koenig: single hover + button,
slash commands, full card edit modes (image/gallery/video/audio/file/embed/
bookmark/callout/toggle/button/HTML/code), inline format toolbar, keyboard
shortcuts, drag-drop uploads, oEmbed/bookmark metadata fetching.
Includes lexical_to_sx converter for backfilling existing posts, KG card
components matching Ghost's card CSS, migration for sx_content column, and
31 converter tests.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
giles
341fc4cf28