Add a Dedicated Demo Script for Lease Recovery

[chendbox]

Summary

Create a dedicated script that runs the lease recovery demo with less manual terminal work.

Why This Matters

MLIS''s lease recovery flow is a signature demo. A single command or guided script would make workshops, videos, and first-time evaluations much easier.

Scope

Possible behavior:

• submit a long-running sleep job
• resolve the active worker handling the job
• kill that worker
• poll job status until reassignment and final success
• print useful progress messages

Acceptance Criteria

• demo script is easy to run locally
• output is understandable without reading the implementation
• script helps confirm reassignment and eventual success
• docs mention how to use it

Good Starting Points

• scripts/
• README.md
• docs/runbooks/local-demo.md