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/assetCommands.ts

@@ -104,7 +104,10 @@ export class RenameAssetCommand implements Command {
   readonly label = 'Rename asset';
   private previousName = '';
 
-  constructor(private readonly assetId: string, private readonly name: string) {}
+  constructor(
+    private readonly assetId: string,
+    private readonly name: string,
+  ) {}
 
   execute(project: Project): void {
     const asset = requireAsset(project, this.assetId);
@@ -119,7 +122,11 @@ export class RenameAssetCommand implements Command {
 
 /** The half of `SetBagValueCommand` both asset property edits share: the bag is the asset's own. */
 abstract class AssetPropertyCommand extends SetBagValueCommand<Asset> {
-  protected constructor(private readonly assetId: string, key: string, label: string) {
+  protected constructor(
+    private readonly assetId: string,
+    key: string,
+    label: string,
+  ) {
     super(key, label);
   }
 
@@ -134,7 +141,11 @@ abstract class AssetPropertyCommand extends SetBagValueCommand<Asset> {
 
 /** Sets an asset property (coerced against its schema entry). */
 export class SetAssetPropertyCommand extends AssetPropertyCommand {
-  constructor(assetId: string, key: string, private readonly value: PropertyValue) {
+  constructor(
+    assetId: string,
+    key: string,
+    private readonly value: PropertyValue,
+  ) {
     super(assetId, key, `Set ${key}`);
   }