[Future] Onboard another environment to LastCode reliability workflows

[lastobelus]

Future scope

Make it straightforward to onboard someone else's environment to the LastCode checkpoint, build, recovery, and carry-replay system while keeping the workflow safe, understandable, and repeatable.

This is future work and is outside the initial checkpoint containment and production carry-replay scope.

Acceptance checklist

• Define the supported prerequisites and a safe, environment-neutral setup path.
• Detect missing tools, configuration, permissions, and incompatible state with actionable explanations.
• Provide a disposable validation mode that proves checkpoint, build, recovery, and update contracts without touching shared live state.
• Make pairing, ownership, and access boundaries explicit for a new maintainer.
• Document how to inspect failures and resume work without relying on private machine knowledge.
• Verify the onboarding flow on a clean environment and keep routine operation free of additional daily steps.