ci: build Linux amd64 release on Ubuntu 22.04

[lorenzozanee]

What does this PR do?

Change the standard Linux amd64 build and release-artifact smoke runner to Ubuntu 22.04, and add a workflow contract assertion. This tests the requested glibc 2.35 baseline. The issue did not include the mise asset URL or hash, so this does not establish which published artifact failed or prove its runtime behavior.

The repository requires maintainer design discussion for CI workflow changes. No maintainer approval is recorded; requesting @DeusData review before merge. Prepared with Codex, an AI agent, on behalf of @lorenzozanee.

Fixes #2486

Local checks: bash tests/test_venue_parity_contract.sh passed; workflow YAML parsing and git diff --check passed. bash scripts/test.sh reported 8,771 passed and 21 failed due to workspace permission checks (0775); bash scripts/lint.sh could not run because clang-tidy and cppcheck are unavailable. Ubuntu 22.04 release artifact build/runtime and remote CI remain unverified.

Checklist

• Every commit is signed off (git commit -s) — required, CI rejects
  unsigned commits (DCO, see CONTRIBUTING.md)
• Tests pass locally (make -f Makefile.cbm test)
• Lint passes (make -f Makefile.cbm lint-ci)
• New behavior is covered by a test (reproduce-first for bug fixes)

[github-actions]

Thanks for opening this — it has been seen, and it is queued.

This note is automated, but it is not a brush-off: it exists so you know where your PR stands instead of having to guess from silence.

Current review status: working through a backlog. 0.9.1-rc.1 is out, so the release freeze that held reviews is over — but it left a large queue of open pull requests behind it, and we are reading through them oldest-first. The background is in discussion #1144.

What that means for this PR, concretely:

• It will not be closed for inactivity. No stale bot touches pull requests here.
• It may still sit a while before a human reads it. That is on us, not on you.
• Older PRs are read first, so a recent one is not being skipped — it is behind a queue.

Things that will genuinely speed it up whenever review does happen:

• Keep it rebased on main — the tree is moving quickly right now, and a conflicting branch cannot be reviewed as the diff you intended.
• Get CI green, or say which failures you believe are pre-existing.
• Keep the change to one claim. Bundled features and refactors get split before they get merged, which costs you a round trip.
• Every commit needs a sign-off (git commit -s) — CI enforces DCO.

If this fixes a bug, a reproduction we can run is worth more than a description of the symptom.

Thanks for contributing, and sorry in advance for the wait.