Isolate explicit S/R gate target ladder

app/services/sr_service.py

@@ -451,8 +451,9 @@ def detect_sr_levels_legacy(
                 if explicit_range_grid
                 else _legacy_volume_profile_nodes(highs, lows, closes, volumes)
             )
+            method = "range_grid" if explicit_range_grid else "volume_profile"
             for price in nodes:
-                candidates.append((float(price), "volume_profile"))
+                candidates.append((float(price), method))
         except ValidationError:
             pass
     if include_pivots: