Make install-test job a blocking dependency of release

[mikevitelli]

Context

release.yml creates a GitHub Release with a .deb artifact, but the install-test job (Docker arm64 verification) is not a blocking dependency. A broken .deb could be released if the install test fails after the release job completes.

Proposed approach

1. Make the release job needs: [install-test] so it only runs after Docker verification passes
2. Add a post-install smoke test in the Docker container (run uconsole --version, verify service files exist)
3. Fail the entire release pipeline if install test fails

Acceptance criteria

• Release job depends on install-test passing
• Install test includes basic smoke test (not just dpkg exit code)
• Failed install test blocks release creation