test(desktop): store-level dismiss/restore round-trip for auto projects

Adds a layout-store test beside the existing menu test: dismiss hides
the row, restore brings it back, restore is idempotent. Also drops an
unused helper the salvaged test file left behind.

apps/desktop/src/app/chat/sidebar/projects/project-menu.test.tsx

@@ -97,8 +97,6 @@ const autoProject = {
   path: '/auto/repo'
 } as unknown as SidebarProjectTree
 
-const tipTrigger = (el: HTMLElement) => el.closest('[data-slot="tooltip-trigger"]')
-
 const openTriggerMenu = (trigger: HTMLElement) => {
   // Radix's dropdown trigger opens on pointerdown (a synthetic 'click' fireEvent
   // alone won't do it), so fire the full mouse sequence a real click produces —

apps/desktop/src/store/layout-dismissed-projects.test.ts

@@ -1,6 +1,10 @@
-import { describe, expect, it } from 'vitest'
+import { beforeEach, describe, expect, it } from 'vitest'
 
-import { filterVisibleProjects } from './layout'
+import { $dismissedAutoProjectIds, dismissAutoProject, filterVisibleProjects, restoreAutoProject } from './layout'
+
+beforeEach(() => {
+  $dismissedAutoProjectIds.set([])
+})
 
 const auto = (id: string) => ({ id, isAuto: true as const })
 const explicit = (id: string) => ({ id, isAuto: false as const })
@@ -21,4 +25,21 @@ describe('filterVisibleProjects', () => {
     const tree = [explicit('p_real'), auto('/www/gone')]
     expect(filterVisibleProjects(tree, ['p_real', '/www/gone']).map(p => p.id)).toEqual(['p_real'])
   })
+
+  it('restores a dismissed auto project (Undo round-trip) and is idempotent', () => {
+    const tree = [auto('/www/hide-me'), auto('/www/stays')]
+    dismissAutoProject('/www/hide-me')
+    expect(filterVisibleProjects(tree, $dismissedAutoProjectIds.get()).map(p => p.id)).toEqual(['/www/stays'])
+
+    restoreAutoProject('/www/hide-me')
+    expect($dismissedAutoProjectIds.get()).toEqual([])
+    expect(filterVisibleProjects(tree, $dismissedAutoProjectIds.get()).map(p => p.id)).toEqual([
+      '/www/hide-me',
+      '/www/stays'
+    ])
+
+    // Restoring an id that isn't dismissed must not throw or mutate the list.
+    restoreAutoProject('/www/hide-me')
+    expect($dismissedAutoProjectIds.get()).toEqual([])
+  })
 })