Each timeline date heading now links to /day/<YYYY-MM-DD>/, a page
holding just that day's photos with a back link to the timeline.
renderDayPages writes one per groupByDay run; the ISO label doubles
as the URL slug.
The day-grouped timeline is now the site root (/, /page/N/); the flat
square grid moves to /grid/ (/grid/page/N/). Both are linked from the
profile header, separated by a divider.
Timeline pages pack whole day-groups until they reach the page size,
never splitting a day across a page boundary, so appended pages never
repeat a date heading — the infinite-scroll handler relies on this.
Page size is configurable via -page-size (default 60), threaded through
the Generator and exposed as services.photogallery.pageSize in the
NixOS module.
New /timeline/ page renders photos grouped into consecutive same-day
runs (ISO date heading plus per-day count), reusing the square grid.
groupByDay collapses the newest-first photo list; the page is not
paginated. Linked from the profile header.
puttaalu