No per-stage timing telemetry #293

Location: runner.py
Severity: MED

There is no record of how long download / analyze / separate / collect took, or on which device. Performance regressions (and the CPU-vs-GPU question) are unanswerable from logs.
One INFO line per job at completion: job=… device=cuda download=12.3s analyze=4.1s separate=88.0s collect=9.2s total=…. Also write it into metadata.json for the failed-jobs quarantine.

From the health report. Part of #272 (Phase 1 — Evidence).