Diagnosed live over the WebView DevTools protocol: a 0 km track had exactly one
usable point. The map block runs (points.length is truthy), but with a single
coordinate fitBounds is skipped, so the Leaflet map never gets a view and never
fires 'load'. With a saved route active, the overlay code then does
`await whenMapReady(map)`, which waits on that 'load' event forever — hanging the
rest of showSessionDetail, so the Delete/Recalc/Export handlers past it never
bind. No exception, just a silent stall (hence "nothing happens on Delete").
Fix: when there are < 2 coords, setView to the single point so the map loads and
whenMapReady resolves. Verified end-to-end via DevTools: the button now binds and
the 0 km track deletes.
(The prior commit moved the handlers out of the `points.length` guard, which
covers a truly 0-point track; this covers the 1-point-with-route hang.)