feat: filter fires chart data by season_months

Pass season_months through to _build_chart_data so only detections in the
selected season are included in the monthly chart output. Adds two unit tests
covering filtered and unfiltered behaviour.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/indicators/fires.py

@@ -37,7 +37,7 @@ class FiresIndicator(BaseIndicator):
         status = self._classify(count)
         trend = self._compute_trend(rows, time_range)
         confidence = self._compute_confidence(rows)
-        chart_data = self._build_chart_data(rows)
+        chart_data = self._build_chart_data(rows, season_months)
 
         if count == 0:
             headline = "No active fires detected"
@@ -187,13 +187,15 @@ class FiresIndicator(BaseIndicator):
         return ConfidenceLevel.LOW
 
     @staticmethod
-    def _build_chart_data(rows: list[dict]) -> dict[str, Any]:
+    def _build_chart_data(rows: list[dict], season_months: list[int] | None = None) -> dict[str, Any]:
         monthly: dict[str, int] = defaultdict(int)
         for row in rows:
             acq = row.get("acq_date", "")
             if acq and len(acq) >= 7:
                 month_key = acq[:7]  # "YYYY-MM"
-                monthly[month_key] += 1
+                month_num = int(month_key[5:7])
+                if season_months is None or month_num in season_months:
+                    monthly[month_key] += 1
 
         sorted_months = sorted(monthly.keys())
         return {

tests/test_indicator_fires.py

@@ -73,3 +73,19 @@ async def test_fires_indicator_green_when_no_fires(fires_indicator, sample_aoi,
 
     assert result.status == StatusLevel.GREEN
     assert "0" in result.headline or "no" in result.headline.lower()
+
+
+def test_build_chart_data_filters_by_season():
+    rows = [{"acq_date": f"2025-{m:02d}-15"} for m in range(1, 13) for _ in range(3)]
+    season_months = [6, 7, 8, 9]
+    result = FiresIndicator._build_chart_data(rows, season_months)
+    assert len(result["dates"]) == 4
+    assert result["dates"][0] == "2025-06"
+    assert result["dates"][-1] == "2025-09"
+    assert all(v == 3 for v in result["values"])
+
+
+def test_build_chart_data_no_season_returns_all():
+    rows = [{"acq_date": f"2025-{m:02d}-15"} for m in range(1, 13)]
+    result = FiresIndicator._build_chart_data(rows, None)
+    assert len(result["dates"]) == 12