feat: add play apps and layout tools

tests/layoutDraw/layoutDrawHistory.test.ts

@@ -0,0 +1,56 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import {
+  commitLayoutDrawHistory,
+  createLayoutDrawHistoryState,
+  redoLayoutDrawHistory,
+  undoLayoutDrawHistory,
+} from '../../src/features/layout/draw/layoutDrawHistory.ts';
+import type { LayoutDrawDocument } from '../../src/features/layout/draw/layoutDrawTypes.ts';
+
+function createDocument(partial?: Partial<LayoutDrawDocument>): LayoutDrawDocument {
+  return {
+    backgroundMode: partial?.backgroundMode ?? 'grid',
+    shapes:
+      partial?.shapes ?? [
+        {
+          id: 'line-1',
+          type: 'line',
+          x1: 10,
+          y1: 20,
+          x2: 10,
+          y2: 180,
+          orientation: 'vertical',
+          label: '',
+        },
+      ],
+  };
+}
+
+test('commits a new snapshot into undo history and clears redo history', () => {
+  const initial = createLayoutDrawHistoryState(createDocument({ shapes: [] }));
+  const committed = commitLayoutDrawHistory(initial, createDocument());
+
+  assert.equal(committed.past.length, 1);
+  assert.equal(committed.future.length, 0);
+  assert.equal(committed.present.shapes.length, 1);
+});
+
+test('undo restores the previous snapshot and redo reapplies it', () => {
+  const initial = createLayoutDrawHistoryState(createDocument({ shapes: [] }));
+  const committed = commitLayoutDrawHistory(initial, createDocument());
+  const undone = undoLayoutDrawHistory(committed);
+  const redone = redoLayoutDrawHistory(undone);
+
+  assert.equal(undone.present.shapes.length, 0);
+  assert.equal(redone.present.shapes.length, 1);
+});
+
+test('does not create duplicate history entries for unchanged documents', () => {
+  const initialDocument = createDocument();
+  const initial = createLayoutDrawHistoryState(initialDocument);
+  const committed = commitLayoutDrawHistory(initial, initialDocument);
+
+  assert.equal(committed, initial);
+  assert.equal(committed.past.length, 0);
+});