Isolate explicit S/R gate target ladder

tests/unit/test_detect_sr_levels.py

@@ -277,6 +277,30 @@ class TestDetectSrLevels:
         assert sorted(deployed) == explicit
         assert len(explicit) == 20
 
+    def test_explicit_target_ladder_preserves_full_legacy_mechanics(self):
+        highs, lows, closes, volumes = _make_series(n=500)
+        deployed = detect_sr_levels_legacy(highs, lows, closes, volumes)
+        explicit = detect_sr_levels_legacy(
+            highs,
+            lows,
+            closes,
+            volumes,
+            explicit_range_grid=True,
+        )
+
+        def mechanics(level):
+            return {
+                key: value
+                for key, value in level.items()
+                if key not in {"detection_method", "sources"}
+            }
+
+        assert [mechanics(level) for level in explicit] == [
+            mechanics(level) for level in deployed
+        ]
+        assert any("range_grid" in level["sources"] for level in explicit)
+        assert all("volume_profile" not in level["sources"] for level in explicit)
+
     def test_explicit_range_grid_is_volume_independent(self):
         highs, lows, closes, volumes = _make_series(n=500)
         shifted_volumes = [volume * (i + 1) for i, volume in enumerate(volumes)]