Fix weather display: use issued_at for zero-hour truth and deduplicate forecasts

- Changed save_zero_hour_forecast_as_truth to use issued_at instead of target_at for resolved_at timestamp
- Added window function to deduplicate forecast points, keeping only the most recent for each (target_at, horizon_hours)
- Limits resolved truth query to current time to prevent future points from displaying
- This fixes vertical lines in the chart caused by duplicate forecasts and ensures truth data displays correctly

gibil/classes/weather_store.py

@@ -216,8 +216,20 @@ class WeatherStore:
                         temperature_c,
                         shortwave_radiation_w_m2,
                         cloud_cover_pct
+                    FROM (
+                        SELECT
+                            issued_at,
+                            target_at,
+                            horizon_hours,
+                            source,
+                            temperature_c,
+                            shortwave_radiation_w_m2,
+                            cloud_cover_pct,
+                            ROW_NUMBER() OVER (PARTITION BY target_at, horizon_hours ORDER BY issued_at DESC) as rn
                         FROM weather_forecast_points
                         WHERE target_at >= %s AND target_at <= %s
+                    ) as ranked
+                    WHERE rn = 1
                     ORDER BY target_at, horizon_hours
                     LIMIT 5000
                     """,