M7 epic: Lab templates and readiness

[Andreas-Froyland]

Tracking issue. Dependency and status checklists only — implementation stays in narrow linked issues.

Outcome

Versioned Proxmox-backed Lab templates produce a guest that is verifiably ready for use, with bootstrap profiles and project setup applied.

Supersedes

Replaces the disposable test-environment portion of #2's primary use case (Ubuntu Desktop, Bazzite, and Windows test VMs) and the "boot -> provision -> deploy" part of #3's golden-image workflow.

Depends on

• M6 template/clone/snapshot operations
• M3 clone-to-ready workflow
• M4 reconciliation and profiles

Scope checklist

• Versioned Lab template resources with provenance
• Readiness probes distinguishing "provisioned" from "ready"
• Bootstrap profile application and project setup on a fresh guest
• Explicit failure state when a guest never reaches ready

Constrained by

• docs/PLAN.md — M7; docs/architecture/lab.md; ADR-0008
• TTL begins at ready, not at provisioning start

Non-goals

• Guest OS image building
• Scheduler capacity and fairness