Add external container-escape prevention and containment-integrity detection

[justsml]

This was generated by AI during triage.

Goal

Prevent and independently detect container-escape precursors and containment violations for agent workloads.

Scope

• Require MicroVM isolation for designated high-risk workload classes and fail closed when unavailable.
• Add external runtime-observation adapters for namespace, mount, privilege, container-runtime socket, firewall, device, and unexpected listener activity.
• Persist containment events as Artifacts and add deterministic containment-integrity block gates.
• Ensure in-container telemetry is never the sole source of a safety verdict.

Acceptance criteria

• High-risk execution cannot silently fall back from MicroVM to a plain container.
• Verified violations halt the run and preserve forensic evidence.
• Synthetic tests cover both detected violations and normal allowed operation.