Mesh Optimizer: sibling StaticMesh duplicate remover (UE 5.7)

Editor plugin that detects geometrically-identical sibling StaticMeshes across a
level, rebases each placement onto one canonical mesh with a corrected transform
(W' = D * W, verified by exact vertex matching), and can collapse groups into HISM.
Native Slate tool panel + BlueprintCallable UOptimizerSubsystem.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Source/OptimizerEditor/Private/OptimizerMatcher.h

@@ -0,0 +1,35 @@
+// Copyright IHY.
+#pragma once
+
+#include "CoreMinimal.h"
+#include "OptimizerTypes.h"
+#include "OptimizerGeometry.h"
+
+/**
+ * Recovered rigid (optionally mirrored/scaled) delta that maps CANONICAL-local geometry onto
+ * MEMBER(sibling)-local geometry. Stored as a UE row-vector matrix: v_member = v_canon * CanonToMember.
+ * This is exactly the D in the corrective formula W' = D * W.
+ */
+struct FOptDelta
+{
+	bool bValid = false;
+	bool bIdentity = false;   // delta is (within tolerance) identity -> swap mesh, keep transform
+	bool bMirrored = false;   // recovered rotation is improper (det < 0) -> negative-scale instance
+	bool bScaled = false;     // uniform scale != 1 folded in
+	double Scale = 1.0;
+	double MaxDev = 0.0;      // worst per-vertex deviation under the delta, cm
+	double Rms = 0.0;
+	FMatrix CanonToMember = FMatrix::Identity;
+};
+
+namespace OptimizerMatcher
+{
+	/** Cheap bucket test: are these two fingerprints compatible enough to attempt recovery? */
+	bool FingerprintCompatible(const FOptMeshGeom& A, const FOptMeshGeom& B, const FOptimizerScanSettings& Settings);
+
+	/**
+	 * Recover the delta mapping canonical-local (A) onto member-local (B). Both A.Positions and
+	 * B.Positions must be populated. Returns false if no candidate passes verification.
+	 */
+	bool RecoverDelta(const FOptMeshGeom& A, const FOptMeshGeom& B, const FOptimizerScanSettings& Settings, FOptDelta& Out);
+}