fix(setup-runner): support ubuntu-26.04 runners and skip resolute apt source (#541)

[castrojo]

What does this change?

Fixes #541.

On ubuntu-26.04 (and ubuntu-26.04-arm) runners, bootc-build/setup-runner failed immediately during Select podman source (formerly Add Ubuntu resolute apt source) because of test "${IDV}" = "ubuntu-24.04" under set -e, blocking every consumer's Renovate runner bump (e.g. projectbluefin/dakota#1592, projectbluefin/bluefin#1307, projectbluefin/common#1142).

This PR:

• Replaces the 24.04 assertion with a case "${IDV}" block.
• For ubuntu-24.04, configures the resolute apt source and sets output install-from-resolute=true.
• For ubuntu-26.04, verifies podman --version major >= 5 at runtime, emits an informational notice, and sets output install-from-resolute=false, safely skipping the apt repository and upgrade.
• For any other runner image, fails fast with an actionable error.
• Gates downstream apt cache key, restore, apt install, and cache save steps on install-from-resolute == 'true'.
• Updates documentation in docs/skills/composite-actions/action-reference.md, docs/skills/composite-actions.md, and docs/skills/testing.md.
• Expands tests/bats/test_setup_runner.bats with unit tests for all branches and adds a drift guard verifying action.yml structure.

Consumer validation

Consumer PR: projectbluefin/bluefin#1307
Consumer CI run: TODO
Out-of-org consumer impact: N/A — backward compatible with existing ubuntu-24.04 runners while unblocking ubuntu-26.04.

• Opened a draft consumer PR pinned to this branch SHA
• Linked a passing consumer CI run that exercised this change
• Evaluated out-of-org consumers (ublue-os/aurora, ublue-os/bazzite) and documented the impact above

Checklist

• I am using an agent and I take responsibility for this PR (if AI-assisted)
• Conventional commit message (feat:, fix:, chore:, etc.)
• No hardcoded secrets or credentials

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

[hivecommons-hive]

🐝 Possible duplicate

This PR changes exactly the same files as #542, which was opened first:

• survivor (suggested): fix(setup-runner): support ubuntu-26.04 runners and skip resolute pin #542 — fix(setup-runner): support ubuntu-26.04 runners and skip resolute pin
• fix(setup-runner): support ubuntu-26.04 runners and skip resolute apt source (#541) #549 — fix(setup-runner): support ubuntu-26.04 runners and skip resolute apt source (setup-runner asserts ubuntu-24.04 and blocks every consumer's ubuntu-26.04 runner bump #541) ← this PR

Evidence — identical changed-file set (5 file(s)):

• bootc-build/setup-runner/action.yml
• docs/skills/composite-actions.md
• docs/skills/composite-actions/action-reference.md
• docs/skills/testing.md
• tests/bats/test_setup_runner.bats

---

This is a suggestion, not a verdict. Hive will not close, label, approve or merge anything here — a human decides.

It was produced by comparing changed-file sets across open PRs, which is a candidate generator: PRs that share a file are not necessarily the same work. Here the patches DIFFER, so this is the weaker tier: dependency-bump PRs that edit one shared manifest, and unrelated fixes to one busy file, both land in it. Read the diffs before acting.

[hivecommons-hive]

style

• (low) tests/bats/test_setup_runner.bats:19-56 — PODMAN_SOURCE_LOGIC is labeled "Verbatim from bootc-build/setup-runner/action.yml" (and the file header says "Keep these snippets verbatim"), but it already drifts from the action at merge time: the test snippet has an extra comment line # before skipping the apt source. that action.yml:77 does not. The new drift guard (test_setup_runner.bats:391-398) only greps a few structural lines, so it won't catch this or future divergence. Suggest syncing the comment and/or tightening the guard.

No findings from: correctness, security, intent-alignment, docs-currency.

— hive: agent=reviewer backend=copilot model=claude-fable-5 copilot=1.0.78