test(conformance): cover sandbox lifecycle in archives

[elezar]

Summary

Add driver-agnostic sandbox lifecycle coverage to the conformance nextest archive. The archive runs smoke and lifecycle targets inside the provisioned t-machine guest; this PR is stacked on #3372.

Related Issue

Related to #2973, #2974, and #2976 through #3371 and #3372. No issue is closed independently by this stacked test-coverage increment.

Changes

• Add a lifecycle scenario that verifies stop/start workspace preservation and deletion of a stopped sandbox.
• Add a separately selectable lifecycle nextest target to the conformance CLI suite.
• Rename the t-machine guest suite and playbook from smoke to conformance.
• Configure the guest CLI local gateway entry once during scenario installation, before the archived conformance tests run.

Testing

• cargo test -p openshell-conformance
• nix run .#build-artifacts-test-archives packages smoke and lifecycle targets
• nix build .#tmachine-config --no-link
• Ansible syntax checks for the t-machine gateway and conformance playbooks
• nix run .#tmachine -- test ubuntu-docker-rootful conformance
• nix run .#tmachine -- test fedora-podman-rootless conformance
• nix run .#tmachine -- test fedora-podman-rootful conformance

Checklist

• Follows Conventional Commits
• Commits are signed off (DCO)

[SDAChess]

Minor nitpicks but overall looks good

[copy-pr-bot]

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