Add ESLint and Prettier, and close the node test gaps

Tooling:
- Prettier as the single formatting authority (110 columns, single quotes,
  measured against the existing style); Markdown excluded because table-cell
  padding turns the README glossary into 1000-character lines.
- Type-aware ESLint ending in eslint-config-prettier, so a rule always means
  "this is a bug", never "this looks different".
- .editorconfig and an `npm run check` that runs typecheck, lint, format and
  tests in one go.

Findings fixed on the first run: three more duplicate imports, four
String(unknown) calls (parameter types narrowed instead of casts), two dead
initialisers, two redundant casts, a console.log for a real error. Two
warnings were false here and are disabled with a reason in place.

Tests 132 -> 269:
- node-catalog.test.ts covers every node with a run(), with a guard that fails
  when a new node has no row.
- behavior-events.test.ts covers the ten event nodes through a running World,
  checking timing rather than existence.
- Input's state machine (press/release/releaseAll) is reachable without DOM
  events now; the DOM handlers are thin adapters.

Compare fell back to == without a configured operator although the schema
default is <; aligned.

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

src/core/commands/sceneObjectCommands.ts

@@ -2,7 +2,13 @@ import { newId } from '../ids';
 import { isPlaceableType } from '../model/AssetTypes';
 import { instantiateContainer } from '../model/container';
 import { isSelfOrAncestor, localPositionFor, removeSubtrees, worldPosition } from '../model/hierarchy';
-import { type Position, type PropertyBag, type PropertyValue, toPosition, type Vec2 } from '../model/Properties';
+import {
+  type Position,
+  type PropertyBag,
+  type PropertyValue,
+  toPosition,
+  type Vec2,
+} from '../model/Properties';
 import type { Project } from '../model/Project';
 import { createSceneObject, type SceneObject } from '../model/SceneObject';
 import { coerceValue } from '../properties/PropertySchema';
@@ -53,7 +59,10 @@ export class RemoveSceneObjectsCommand implements Command {
   readonly label: string;
   private removed: Removed<SceneObject>[] = [];
 
-  constructor(private readonly sceneId: string, private readonly objectIds: readonly string[]) {
+  constructor(
+    private readonly sceneId: string,
+    private readonly objectIds: readonly string[],
+  ) {
     this.label = objectIds.length === 1 ? 'Remove object' : 'Remove objects';
   }
 
@@ -83,7 +92,11 @@ export class MoveSceneObjectCommand implements Command {
   readonly label = 'Move object';
   private previous: Position = { x: 0, y: 0, z: 0 };
 
-  constructor(private readonly sceneId: string, private readonly objectId: string, private readonly position: Position) {}
+  constructor(
+    private readonly sceneId: string,
+    private readonly objectId: string,
+    private readonly position: Position,
+  ) {}
 
   execute(project: Project): void {
     const object = requireObject(project, this.sceneId, this.objectId);
@@ -105,7 +118,11 @@ export class SetEditorOffsetCommand implements Command {
   readonly label = 'Editor offset';
   private previous: Vec2 = { x: 0, y: 0 };
 
-  constructor(private readonly sceneId: string, private readonly objectId: string, private readonly offset: Vec2) {}
+  constructor(
+    private readonly sceneId: string,
+    private readonly objectId: string,
+    private readonly offset: Vec2,
+  ) {}
 
   execute(project: Project): void {
     const object = requireObject(project, this.sceneId, this.objectId);
@@ -122,7 +139,11 @@ export class RenameSceneObjectCommand implements Command {
   readonly label = 'Rename object';
   private previous = '';
 
-  constructor(private readonly sceneId: string, private readonly objectId: string, private readonly name: string) {}
+  constructor(
+    private readonly sceneId: string,
+    private readonly objectId: string,
+    private readonly name: string,
+  ) {}
 
   execute(project: Project): void {
     const object = requireObject(project, this.sceneId, this.objectId);
@@ -137,7 +158,12 @@ export class RenameSceneObjectCommand implements Command {
 
 /** The half of `SetBagValueCommand` both override edits share: the bag is the object's overrides. */
 abstract class OverrideCommand extends SetBagValueCommand<SceneObject> {
-  protected constructor(private readonly sceneId: string, private readonly objectId: string, key: string, label: string) {
+  protected constructor(
+    private readonly sceneId: string,
+    private readonly objectId: string,
+    key: string,
+    label: string,
+  ) {
     super(key, label);
   }
 
@@ -152,7 +178,12 @@ abstract class OverrideCommand extends SetBagValueCommand<SceneObject> {
 
 /** Sets a per-object override of an asset property. */
 export class SetOverrideCommand extends OverrideCommand {
-  constructor(sceneId: string, objectId: string, key: string, private readonly value: PropertyValue) {
+  constructor(
+    sceneId: string,
+    objectId: string,
+    key: string,
+    private readonly value: PropertyValue,
+  ) {
     super(sceneId, objectId, key, `Override ${key}`);
   }
 
@@ -180,9 +211,16 @@ export class ClearOverrideCommand extends OverrideCommand {
  */
 export class SetParentCommand implements Command {
   readonly label = 'Set parent';
-  private previous: { parentId: string; position: Position } = { parentId: '', position: { x: 0, y: 0, z: 0 } };
+  private previous: { parentId: string; position: Position } = {
+    parentId: '',
+    position: { x: 0, y: 0, z: 0 },
+  };
 
-  constructor(private readonly sceneId: string, private readonly objectId: string, private readonly parentId: string) {}
+  constructor(
+    private readonly sceneId: string,
+    private readonly objectId: string,
+    private readonly parentId: string,
+  ) {}
 
   execute(project: Project): void {
     const scene = requireScene(project, this.sceneId);
@@ -190,7 +228,8 @@ export class SetParentCommand implements Command {
     if (this.parentId) {
       if (this.parentId === this.objectId) throw new CommandError('An object cannot be its own parent');
       requireObject(project, this.sceneId, this.parentId);
-      if (isSelfOrAncestor(scene, this.objectId, this.parentId)) throw new CommandError('An object cannot be parented to one of its own children');
+      if (isSelfOrAncestor(scene, this.objectId, this.parentId))
+        throw new CommandError('An object cannot be parented to one of its own children');
     }
     this.previous = { parentId: object.parentId, position: { ...object.position } };
     const world = worldPosition(scene, object);