feat(acq): teardown/recreate lifecycle - auto-snapshot hook and one-shot recreate wrapper

[mogul]

Part of #493.

Summary

Build the teardown/recreate lifecycle conveniences on top of the native acq snapshot / acq restore verbs (msb; sbx unsupported). Rebased off the earlier manifest/tar design, which has been superseded.

Scope

• Auto-snapshot-on-teardown hook so a planned reboot or acq rm first captures a full snapshot (acq snapshot) rather than silently dropping agent context.
• One-shot recreate wrapper: snapshot → rm → restore, where restore re-binds current host resources internally — see the --vsock route re-derivation sub-issue.
• Quiesce is handled by the native primitive (msb --guest-flush), not per-kit hooks.

Backend applicability

msb only. On sbx (unsupported) the lifecycle helpers surface the same explicit "unsupported on this backend" message as the underlying verbs.

Acceptance

• acq recreate NAME [OUT] snapshots, removes, then restores NAME on msb.
• acq rm --snapshot NAME [OUT] snapshots before removing and never removes if snapshot fails.
• The lifecycle path preserves full agent context on msb, including SSH signing after restore.