Separate chart S/R from gate target ladder

app/services/sr_service.py

@@ -522,6 +522,30 @@ def detect_sr_levels_legacy(
     return merged
 
 
+def detect_gate_target_ladder(
+    highs: list[float],
+    lows: list[float],
+    closes: list[float],
+    tolerance: float = DEFAULT_TOLERANCE,
+) -> list[dict]:
+    """Build the scanner's internal, volume-free target proposal ladder.
+
+    This is intentionally not human-facing support/resistance. It preserves
+    the production gate's broad 20-bin range grid, unfiltered pivots, touch
+    strength, and merge geometry without performing or claiming a volume
+    profile calculation. The returned levels are transient and must not be
+    persisted as chart S/R.
+    """
+    return detect_sr_levels_legacy(
+        highs,
+        lows,
+        closes,
+        [0] * len(closes),
+        tolerance,
+        explicit_range_grid=True,
+    )
+
+
 def _merge_levels(
     levels: list[dict],
     tolerance: float = DEFAULT_TOLERANCE,