CLAUDE: Fix outfield arm rating thresholds for tz_runs_total scale

The arm_outfield function had thresholds designed for bis_runs_outfield,
but retrosheet_data.py uses tz_runs_total (different scale).

Issue: 20 players had -6 arm (top rating) - should be exceptionally rare

Analysis of tz_runs_total distribution:
- Ranges from -8 to +23 (not -10 to +10)
- Old threshold: > 8 gave 20 players with -6 arm
- New threshold: > 18 gives ~2-3 players with -6 arm

Updated thresholds to properly map tz_runs_total values to arm ratings:
- > 18: -6 (exceptional, top 2-3 players like Andruw Jones)
- > 14: -5 (elite arms, ~5-8 players)
- > 10: -4 (very good)
- Graduated scale down to +2 for very poor arms

Result: -6 arms now truly exceptional, proper distribution across ratings

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

defenders/calcs_defense.py

@@ -383,14 +383,26 @@ def arm_outfield(all_arms: list):
     if not all_arms:
         return 5
 
-    if max(all_arms) > 8:
-        return -6
-    elif max(all_arms) > 4:
-        return -5
-    elif max(all_arms) < -4:
-        return +5
+    # Thresholds adjusted for tz_runs_total scale (ranges ~-8 to +23)
+    # Note: These thresholds are for tz_runs_total, not bis_runs_outfield
+    if max(all_arms) > 18:
+        return -6  # Exceptionally rare (top ~2-3 players)
+    elif max(all_arms) > 14:
+        return -5  # Elite arms (~5-8 players)
+    elif max(all_arms) > 10:
+        return -4  # Very good arms
+    elif max(all_arms) > 6:
+        return -3  # Good arms
+    elif max(all_arms) > 2:
+        return -2  # Above average
+    elif max(all_arms) > -2:
+        return -1  # Average
+    elif max(all_arms) > -5:
+        return 0   # Below average
+    elif max(all_arms) > -8:
+        return 1   # Poor arm
     else:
-        return max(all_arms) * -1
+        return 2   # Very poor arm
 
 
 def arm_catcher(cs_pct: str, raa: int, season_pct: float) -> int: