Update gitlab-ci to 0.19.0
Summary
- Bumps gitlab-ci from 0.18.0 to 0.19.0 in the dev flake (
dev/flake.nix) and CI template include (.gitlab-ci.yml) for Nixica Unification 1.0 consistency. - Updates
dev/flake.lockto track the new0.19.0tag.
This is Tier 1 work from the consistency audit in horizon-flake-parts!28 (merged).