The earliest notes (saved before the previous commit added id
tracking) have no properties.id — update/delete target a feature by
that id, so offering Edit/Delete for one without it just 404s
("Could not delete/save the note", the generic fetch-failure alert).
The popup no longer offers Edit/Delete without an id. New
rake gpx:backfill_note_ids assigns one to any pre-existing Note
feature missing it, so already-saved notes become editable again too
— run once against wherever data/gpx actually lives (e.g. inside the
deployed container).