[test] replace arbitrary setTimeout with vi.waitFor for better test reliability - addresses review feedback

Replaces brittle setTimeout(50) with vitest's vi.waitFor() which polls
for the expected condition. This eliminates flaky test failures on slower
systems while maintaining fast execution when conditions are met quickly.

Author: christian-byrne

tests-ui/tests/renderer/core/layout/layoutStore.test.ts

@@ -1,4 +1,4 @@
-import { beforeEach, describe, expect, it } from 'vitest'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
 
 import { layoutStore } from '@/renderer/core/layout/store/layoutStore'
 import {
@@ -165,10 +165,11 @@ describe('layoutStore CRDT operations', () => {
       actor: layoutStore.getCurrentActor()
     })
 
-    // Wait for async notification
-    await new Promise((resolve) => setTimeout(resolve, 50))
+    // Wait for onChange callback to be called (uses setTimeout internally)
+    await vi.waitFor(() => {
+      expect(changes.length).toBeGreaterThanOrEqual(1)
+    })
 
-    expect(changes.length).toBeGreaterThanOrEqual(1)
     const lastChange = changes[changes.length - 1]
     expect(lastChange.source).toBe('vue')
     expect(lastChange.operation.actor).toBe('user-123')
@@ -198,11 +199,14 @@ describe('layoutStore CRDT operations', () => {
     const newBounds = { x: 40, y: 60, width: 220, height: 120 }
     layoutStore.batchUpdateNodeBounds([{ nodeId, bounds: newBounds }])
 
-    await new Promise((resolve) => setTimeout(resolve, 50))
+    // Wait for onChange callback to be called (uses setTimeout internally)
+    await vi.waitFor(() => {
+      expect(changes.length).toBeGreaterThan(0)
+      const lastChange = changes[changes.length - 1]
+      expect(lastChange.operation.type).toBe('batchUpdateBounds')
+    })
 
-    expect(changes.length).toBeGreaterThan(0)
     const lastChange = changes[changes.length - 1]
-    expect(lastChange.operation.type).toBe('batchUpdateBounds')
     if (lastChange.operation.type === 'batchUpdateBounds') {
       expect(lastChange.nodeIds).toContain(nodeId)
       expect(lastChange.operation.bounds[nodeId]?.bounds).toEqual(newBounds)