Computes for the Manager At-Risk heatmap (Phase 4 tablet redesign).
Non-stored — recomputed on /fp/manager/at_risk read; that endpoint
caches its full payload for 60s so the cost is bounded.
bottleneck_score = active_step_count * avg_wait_minutes
avg_wait_minutes = rolling-7-day avg of (date_started - create_date)
Work centres with high score show red in the heatmap — combination
of queue length AND average wait time.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>