Scrum 84 container registry tau

[Mateusz-Dobrzynski]

Introduced changes
This pull request introduces publishing tau docker images via GitHub Container Registry on pushing to the master branch.

Testing
- [ ] I have covered my code with tests.
- [ ] I have run integration tests with cargo test --tests and ensured that they pass.

• Using this pull request, I published the image and pulled it onto my local machine. One last check will be required after merging this PR (i.e. to see whether the new version gets published after the merge).

# docker run ghcr.io/debatecore/tau:latest 
Unable to find image 'ghcr.io/debatecore/tau:latest' locally
latest: Pulling from debatecore/tau
Digest: sha256:124deba5176b3cb61861199c681ec4cbf1ddd39cbaeb3e1b80ade0f99f2d6d88
Status: Downloaded newer image for ghcr.io/debatecore/tau:latest
2026-06-02T12:50:34.896493Z  INFO tau::setup: Response cannon spinning up...
2026-06-02T12:50:34.896522Z  INFO tau::setup: Current version: 0.1.16

[arsansomuncu]

Requested changes are approved.