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>

Optimizer.uplugin

@@ -0,0 +1,21 @@
+{
+	"FileVersion": 3,
+	"Version": 1,
+	"VersionName": "0.1.0",
+	"FriendlyName": "Mesh Optimizer",
+	"Description": "Editor tool: detect geometrically-identical sibling StaticMeshes across level actors, reassign every user to one canonical mesh with a pivot/rotation-corrected transform, so the set can be converted to HISM.",
+	"Category": "Editor",
+	"CreatedBy": "IHY",
+	"EnabledByDefault": true,
+	"CanContainContent": false,
+	"IsBetaVersion": true,
+	"IsExperimentalVersion": false,
+	"Installed": false,
+	"Modules": [
+		{
+			"Name": "OptimizerEditor",
+			"Type": "Editor",
+			"LoadingPhase": "Default"
+		}
+	]
+}