Briefer command fails to pull docker images

Hi, when running briefer for the first time I got errors:

```
Downloading image briefercloud/briefer:latest...
Error: underlying stream is not seekable
Traceback (most recent call last):
File "/home/icarito/Proyectos/L/briefer-local/venv/bin/briefer", line 8, in
sys.exit(main())
^^^^^^
File "/home/icarito/Proyectos/L/briefer-local/venv/lib/python3.12/site-packages/briefer/main.py", line 251, in main
start_or_run_container(client, container_name, args.image, args.detach)
File "/home/icarito/Proyectos/L/briefer-local/venv/lib/python3.12/site-packages/briefer/main.py", line 106, in start_or_run_container
pull_image(client, image)
File "/home/icarito/Proyectos/L/briefer-local/venv/lib/python3.12/site-packages/briefer/main.py", line 191, in pull_image
layer_output[layer_id] = sys.stdout.tell()
^^^^^^^^^^^^^^^^^
io.UnsupportedOperation: underlying stream is not seekable
```

I was able to get past them with redirecting the output of the `briefer` command to a logfile (e.g. `briefer > init.log`)

I'm running it on Manjaro (Archlinux derivative).
Tried it both and failed both with bash and zsh.

Start in briefer/main.py, especially pull_image, and reproduce the first-run briefer command on a terminal without redirecting stdout. Inspect the failing stdout.tell() path and verify that the image pull completes normally when output is not redirected; no specific test file is mentioned in the issue.

Written by the indexing model from the issue text.