feat: scene traps, material legends, and scene editor window

Add trap overlays with session state, material legend editor/panel, and a dedicated scene editor window wired through IPC and project persistence.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/main/materials/materialsOverlayStore.ts

@@ -14,6 +14,7 @@ function emptyState(): MaterialsOverlayState {
     revision: 1,
     activeMaterialId: null,
     layout: { ...DEFAULT_MATERIALS_OVERLAY_LAYOUT },
+    legendLayout: { ...DEFAULT_MATERIALS_OVERLAY_LAYOUT, cx: 0.82, cy: 0.5, scale: 0.85 },
     zoomTool: null,
   };
 }
@@ -25,6 +26,16 @@ function initialLayout(rotationDeg?: number): MaterialsOverlayLayout {
   });
 }
 
+function initialLegendLayout(): MaterialsOverlayLayout {
+  return clampMaterialsLayout({
+    ...DEFAULT_MATERIALS_OVERLAY_LAYOUT,
+    cx: 0.82,
+    cy: 0.5,
+    scale: 0.85,
+    rotationDeg: 0,
+  });
+}
+
 export class MaterialsOverlayStore {
   private state: MaterialsOverlayState = emptyState();
 
@@ -40,6 +51,7 @@ export class MaterialsOverlayStore {
       revision: this.state.revision + 1,
       activeMaterialId: null,
       layout: { ...DEFAULT_MATERIALS_OVERLAY_LAYOUT },
+      legendLayout: initialLegendLayout(),
       zoomTool: null,
     };
     return this.state;
@@ -54,6 +66,7 @@ export class MaterialsOverlayStore {
           revision: this.state.revision + 1,
           activeMaterialId: event.materialId,
           layout: initialLayout(event.rotationDeg),
+          legendLayout: initialLegendLayout(),
           zoomTool: this.state.zoomTool,
         };
         return this.state;
@@ -65,6 +78,7 @@ export class MaterialsOverlayStore {
           revision: this.state.revision + 1,
           activeMaterialId: event.materialId,
           layout: initialLayout(event.rotationDeg),
+          legendLayout: initialLegendLayout(),
           zoomTool: this.state.zoomTool,
         };
         return this.state;
@@ -81,6 +95,19 @@ export class MaterialsOverlayStore {
         };
         return this.state;
       }
+      case 'legendLayout.set': {
+        if (this.state.activeMaterialId === null) return this.state;
+        this.state = {
+          ...this.state,
+          revision: this.state.revision + 1,
+          legendLayout: clampMaterialsLayout({
+            ...this.state.legendLayout,
+            ...event.layout,
+            rotationDeg: 0,
+          }),
+        };
+        return this.state;
+      }
       case 'zoomTool.set': {
         const tool: MaterialsZoomTool = event.tool;
         this.state = {