Fix findUsages/undo/node-lookup bugs, split Viewport and Editor, share command and inspector helpers

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/core/commands/variableCommands.ts

@@ -1,6 +1,7 @@
 import type { PropertyValue } from '../model/Properties';
 import { findUsages, type Project } from '../model/Project';
 import { isCommonProp, type PropertyDef, type VariableKind, variableDef } from '../properties/PropertySchema';
+import { type Removed, removeFirst, restoreAt } from '../util/list';
 import { type Command, CommandError } from './Command';
 import { requireBehavior } from './require';
 
@@ -32,8 +33,8 @@ export class AddVariableCommand implements Command {
 /** Removes a variable together with its default and every instance override. */
 export class RemoveVariableCommand implements Command {
   readonly label: string;
-  private removed?: { def: PropertyDef; index: number; value: PropertyValue | undefined };
-  private overrides: { sceneId: string; objectId: string; value: PropertyValue }[] = [];
+  private removed?: { def: Removed<PropertyDef>; value: PropertyValue | undefined };
+  private overrides: { holderId: string; objectId: string; value: PropertyValue }[] = [];
 
   constructor(private readonly assetId: string, private readonly key: string) {
     this.label = `Remove variable ${key}`;
@@ -41,17 +42,15 @@ export class RemoveVariableCommand implements Command {
 
   execute(project: Project): void {
     const asset = requireBehavior(project, this.assetId);
-    const index = asset.variables.findIndex((v) => v.key === this.key);
-    const def = asset.variables[index];
+    const def = removeFirst(asset.variables, (v) => v.key === this.key);
     if (!def) throw new CommandError(`Variable "${this.key}" not found`);
-    this.removed = { def, index, value: asset.props[this.key] };
-    asset.variables.splice(index, 1);
+    this.removed = { def, value: asset.props[this.key] };
     delete asset.props[this.key];
     this.overrides = [];
-    for (const { scene, object } of findUsages(project, this.assetId)) {
+    for (const { holder, object } of findUsages(project, this.assetId)) {
       const value = object.overrides[this.key];
       if (value === undefined) continue;
-      this.overrides.push({ sceneId: scene.id, objectId: object.id, value });
+      this.overrides.push({ holderId: holder.id, objectId: object.id, value });
       delete object.overrides[this.key];
     }
   }
@@ -59,17 +58,20 @@ export class RemoveVariableCommand implements Command {
   undo(project: Project): void {
     if (!this.removed) return;
     const asset = requireBehavior(project, this.assetId);
-    asset.variables.splice(this.removed.index, 0, this.removed.def);
+    restoreAt(asset.variables, [this.removed.def]);
     if (this.removed.value !== undefined) asset.props[this.key] = this.removed.value;
     const usages = findUsages(project, this.assetId);
     for (const o of this.overrides) {
-      const object = usages.find((u) => u.scene.id === o.sceneId && u.object.id === o.objectId)?.object;
+      const object = usages.find((u) => u.holder.id === o.holderId && u.object.id === o.objectId)?.object;
       if (object) object.overrides[this.key] = o.value;
     }
   }
 }
 
-/** Renames a variable everywhere: definition, default, instance overrides and graph nodes referring to it. */
+/**
+ * Renames a variable everywhere: definition, default, instance overrides (in scenes and in
+ * container templates) and graph nodes referring to it.
+ */
 export class RenameVariableCommand implements Command {
   readonly label: string;