- e621 list/post queries use a 5 minute staleTime and 30 minute gcTime,
so opening a post and coming back shows the same results with no
refetch; global gcTime raised to 30 minutes
- post card links carry their originating search in route state; the
detail back link returns to it and related-post links keep it
- new navigations scroll to top while history back/forward keeps the
previous position
- DText renderer for e621 descriptions (b/i/u/s, sup/sub, code, spoiler,
quote, color, url/wiki/thumb, headings, lists, sections, expand
blocks, named and bare links) built as React elements, no raw HTML
- Spoiler moved to its own component; trailing punctuation no longer
swallowed into links