test(e2e): run VM suite in CI

[drew]

Summary

Run the existing VM end-to-end suites in GitHub Actions on a standard Ubuntu runner with KVM access. This adds virtualization-backed coverage to the core E2E workflow used by labeled PRs and release builds.

Related Issue

None.

Changes

• add a direct ubuntu-24.04 VM E2E job with KVM permissions and required build dependencies
• run VM smoke/host-gateway coverage and the VM gateway-resume regression
• cache Rust artifacts and use the repository-pinned mise toolchain
• document VM CI coverage and local VM E2E commands

Testing

• mise run pre-commit passes
• Unit tests added/updated (not applicable; CI-only change)
• E2E tests added/updated (if applicable)

Checklist

• Follows Conventional Commits
• Commits are signed off (DCO)
• Architecture docs updated (if applicable)

[github-actions]

Label test:e2e applied for 641f724. Open the existing run and click Re-run all jobs to execute with the label set. The run will execute the standard E2E suite after building the required gateway and supervisor images once. The matching required CI gate status on this PR will flip green automatically once the run finishes.