Root cause: avg times were ~2-3 minutes (< 1h). round(0.033, 1) = 0.0
which is falsy in JS, so the frontend showed N/A instead of the value.
Fix (backend): _safe_stats() and team metrics now convert to minutes
when avg < 1 hour, adding a 'unit' field ('min' or 'hrs').
Fix (frontend): use != null instead of truthy check for avg_completion_hours,
MTTD, MTTR — correctly shows 0.0 and uses the unit field to show 'min' or 'hrs'.
5684484fdf