Disk full, cannot access Seafile in browser, how to delete files / free disk space?

I accidentally cluttered my whole disk with files that I uploaded into Seafile. Now, there’s not a single free byte left and I cannot access Seafile in the browser anymore (I get a lot of “no space on disk left” errors everywhere). Since my OS install is Seafile-only I cannot delete anything without corrupting Seafile. There’s no garbage to be collected with seaf-gc.sh. How can I browse and delete files uploaded to Seafile manually from inside the terminal?

I suggest you delete some log files to free space and then try to bring the web back.