Adds a List/Map toggle to the feed and @user profile pages. The map view
plots all filtered activities as sport-coloured tracks on a MapLibre map
with no extra requests (uses preview_coords already in memory). Clicking
a track or list row selects it: pans the map to fit, expands the list
item with key stats, and scrolls it into view.
Davide Scaini
df025873c6