send to a raw target which does not support output redirection

when i attempt to send a raw backup to rsync.net, i get an error like this

```
ERROR: ... sh: echo -e -n "#btrbk-v0.32.5\n# Do not edit this file\n#t=1721757971\nTYPE=raw\nFILE=@documents.20240723T1301.btrfs.xz\nRECEIVED_UUID=3ea5ee09-c573-d143-bae8-4b93e4fb34d9\ncompress=xz\nINCOMPLETE=1\n" | ssh -i '/home/a/.ssh/id_rsa' de3519@rsync.put.gay 'cat > '\''/data2/home/de3519/btr_backup/dog_backup/@documents.20240723T1301.btrfs.xz.info'\'''
ERROR: ... Warning: Output redirection not supported
ERROR: ... Error parsing command: Output redirection not supported
```

i also tried something like

```
echo "123" | ssh rsync.put.gay 'cat > /data2/home/de3519/test123'
```

and i get the same error. it works with non rsync.net remotes, so i suspect this is a limitation of rsync.net

are there alternative upload methods for ssh? or should backup the raw archives to my local storage server and then rsync those backups to rsync.net?

Reproduce the shown SSH command against rsync.net and compare it with a working non-rsync.net remote. Trace the raw backup upload path and its handling of remote output redirection; done means the target is supported or the limitation and an alternative upload method are clearly documented.

Written by the indexing model from the issue text.