Fix elapsed time always showing "0s" in query output

[mattiasgeniar]

Summary

• ./shannon query always displayed "Elapsed: 0s" regardless of how long the workflow had been running
• Root cause: Temporal's deterministic sandbox overrides Date.now() inside workflows to return replay-safe timestamps, so elapsedMs computed workflow-side is always 0
• Fix: compute elapsed time on the client side using Date.now() - progress.startTime for running workflows, falling back to the workflow-reported elapsedMs for completed
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