fetch() has no cross-browser upload progress event, so the upload
path now uses XMLHttpRequest instead -- its upload.progress firing
with loaded === total is the only client-observable signal that the
server has moved from receiving bytes to converting them, worth
surfacing now that a large POI export's conversion (GpxStore#save)
can itself take several seconds on top of the transfer. Multi-file
uploads now also show which file (i of N) is in flight, previously
just a static "Uploading N files..." for the whole batch.
Verified the 401 path still redirects to /login through the new XHR
flow the same way fetch/redirectIfUnauthorized did.
randy
45567fc520