fix: honor explicit calibration horizon

tools/calibrate_torch_thresholds.py

@@ -120,6 +120,7 @@ def main() -> None:
             trend_candles=trend_candles,
             artifact=artifact,
             horizon=horizon,
+            horizon_is_explicit=args.horizon > 0,
             round_trip_cost=round_trip_cost,
             min_candles=max(30, settings.time_series_min_candles),
             calibration_window=args.calibration_window,
@@ -329,6 +330,15 @@ def _calibration_symbols(
     return [str(symbol).strip().upper() for symbol in artifact_symbols if str(symbol).strip()]
 
 
+def _calibration_horizon(entry: dict[str, Any], requested: int, *, explicit: bool) -> int:
+    horizons = _entry_target_horizons(entry)
+    if explicit and requested > 0:
+        if horizons:
+            return min(horizons, key=lambda value: abs(value - requested))
+        return requested
+    return _entry_horizon(entry, requested)
+
+
 def _forecast_records(
     *,
     symbol: str,
@@ -337,6 +347,7 @@ def _forecast_records(
     trend_candles: list[Candle],
     artifact: dict[str, Any],
     horizon: int,
+    horizon_is_explicit: bool,
     round_trip_cost: float,
     min_candles: int,
     calibration_window: int,
@@ -355,7 +366,7 @@ def _forecast_records(
         trend_candles=trend_candles,
     )
     closes = [float(candle.close) for candle in candles]
-    decision_horizon = _entry_horizon(entry, horizon)
+    decision_horizon = _calibration_horizon(entry, horizon, explicit=horizon_is_explicit)
     start = max(min_candles, int(float(entry.get("lookback", 64))))
     end = len(candles) - decision_horizon - 1
     holdout_start_timestamp = int(float(entry.get("holdout_start_timestamp", 0) or 0))