fix(metrics): prevent 0.0 falsy bug for sub-hour timing values

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'.

backend/app/services/operational_metrics_service.py

@@ -17,13 +17,19 @@ from app.models.enums import TestState, TestResult
 
 
 def _safe_stats(values: list[float]) -> dict:
-    """Compute mean, median, min, max from a list of floats."""
+    """Compute mean, median, min, max from a list of floats (in hours).
+    For sub-hour averages, mean_hours is stored as minutes to avoid
+    rounding to 0.0 which is falsy in JavaScript."""
     if not values:
         return None
     sorted_vals = sorted(values)
     n = len(sorted_vals)
+    mean = sum(sorted_vals) / n
+    # Use minutes for sub-hour values to avoid JS falsy 0.0
+    mean_display = round(mean * 60, 1) if mean < 1 else round(mean, 1)
     return {
-        "mean_hours": round(sum(sorted_vals) / n, 1),
+        "mean_hours": mean_display,
+        "unit": "min" if mean < 1 else "hrs",
         "median_hours": round(sorted_vals[n // 2], 1),
         "min_hours": round(sorted_vals[0], 1),
         "max_hours": round(sorted_vals[-1], 1),
@@ -416,7 +422,9 @@ def get_metrics_by_team(db: Session) -> dict:
         if net > 0:
             red_times.append(net / 3600)
     if red_times:
-        red_avg_time = round(sum(red_times) / len(red_times), 1)
+        avg_hours = sum(red_times) / len(red_times)
+        # Use minutes for sub-hour values so rounding to 0.0 doesn't hide data
+        red_avg_time = round(avg_hours * 60, 1) if avg_hours < 1 else round(avg_hours, 1)
 
     # Blue team: count tests that reached the blue evaluation phase
     blue_tests_completed = (
@@ -449,17 +457,23 @@ def get_metrics_by_team(db: Session) -> dict:
         if net > 0:
             blue_times.append(net / 3600)
     if blue_times:
-        blue_avg_time = round(sum(blue_times) / len(blue_times), 1)
+        avg_hours = sum(blue_times) / len(blue_times)
+        blue_avg_time = round(avg_hours * 60, 1) if avg_hours < 1 else round(avg_hours, 1)
+
+    red_avg_raw = sum(red_times) / len(red_times) if red_times else None
+    blue_avg_raw = sum(blue_times) / len(blue_times) if blue_times else None
 
     return {
         "red_team": {
             "tests_completed": red_tests_completed,
             "avg_completion_hours": red_avg_time,
+            "avg_unit": "min" if (red_avg_raw is not None and red_avg_raw < 1) else "hrs",
             "rejection_rate": calculate_rejection_rate(db)["by_red_lead"],
         },
         "blue_team": {
             "tests_completed": blue_tests_completed,
             "avg_completion_hours": blue_avg_time,
+            "avg_unit": "min" if (blue_avg_raw is not None and blue_avg_raw < 1) else "hrs",
             "rejection_rate": calculate_rejection_rate(db)["by_blue_lead"],
         },
     }