The main map page now reads band, selected time, and map
center/zoom from URL params and updates the URL as the user pans,
zooms, picks a band, or scrubs the timeline. Pan/zoom use
push_patch replace-mode so browser history isn't spammed, while
band and time changes push fresh entries.
Also fix the 'Up to date · just now ago' pipeline chip — 'just
now' already reads as an instant so the trailing 'ago' is
redundant. Any older duration keeps it.
Graham McIntire
160439db31