Bug fix
## What is the current behavior?
Read-only users cannot download files because the download feature
requires minting a temporary API key, which is properly blocked for
read-only users.
## What is the new behavior?
Instead of using temporary API keys, we now create signed URLs for the
files to be downloaded. We batch-create signed URLs for an entire
folder's worth of files, requiring only a single management API call,
then use those signed URLs to download the files. This allows read-only
users to download files without needing elevated permissions.
## Additional context
Resolves FE-2737
Charis
8732fc3bd9