Backend:
- POST /api/files/lookup/ reports which MD5s are already in the library
Frontend:
- e621 client extended with post/tag/favorite types and helpers: post
search, post detail, batch posts by id, tag autocomplete, toggle
favorite
- /online: tag search with autocomplete, post grid with rating colors
and in-library badges, numbered pagination, page tag cloud, blacklist
panel and filtered counts from /users/me.json, anonymous hint
- /online/view/🆔 media viewer (sample or original, video support),
taxonomy-colored tags by category, specs sheet, favorite/unfavorite,
description, sources, pools and parent/children thumbnails
- Shared CollapsibleSidebar extracted from the library page; Online
added to the nav, command palette and sidebar toggle