test: unblock vitest 5 (localStorage accessor, hoisted vi.mock)

Two independent breakages from the vitest 4.1.11 -> 5.0.0 bump:

1. vitest 5 no longer shadows the jsdom window globals with writable ones, so
   `global.localStorage = ...` hits jsdom's getter-only accessor and throws
   "Cannot set property localStorage of [object Window] which has only a
   getter". test/setup.ts is a setup file, so both test files failed to
   collect. Object.defineProperty replaces the accessor outright.

2. vitest 5 rejects a vi.mock() call outside module top level instead of
   silently hoisting it. The call sat inside beforeEach, which was already
   misleading -- it is hoisted above the imports and its factory runs once, on
   first import of the mocked module, so it was never re-applied per test.
   Moved to top level, where it actually executes; the beforeEach keeps its
   resetModules/mockClear.

Verified against both vitest 4.1.11 and 5.0.0: 2 files / 9 tests pass on each.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T2BPPeWMdYEmYbN6eGCBSg

app/components/__tests__/OrganizationSwitcher.spec.ts

@@ -14,20 +14,23 @@ const mockOrganizations = [
 // For now, the component is indirectly tested through useOrganizationSelector tests
 // and manual testing shows it works correctly
 
+// vi.mock is hoisted above the imports and the factory runs once, on the first
+// import of the mocked module -- it was never re-applied per test despite sitting
+// in beforeEach. vitest 5 rejects the nested call outright rather than silently
+// hoisting it, so declare it where it actually executes.
+vi.mock('~/composables/useOrganizationSelector', () => ({
+  useOrganizationSelector: () => ({
+    organizations: ref([mockOrganizations[0]]),
+    selectedOrganization: ref(mockOrganizations[0]),
+    selectedOrgId: ref('1'),
+    selectOrganization: mockSelectOrganization,
+  }),
+}))
+
 describe('OrganizationSwitcher - Single Organization', () => {
   beforeEach(() => {
     vi.resetModules()
     mockSelectOrganization.mockClear()
-
-    // Mock with single organization
-    vi.mock('~/composables/useOrganizationSelector', () => ({
-      useOrganizationSelector: () => ({
-        organizations: ref([mockOrganizations[0]]),
-        selectedOrganization: ref(mockOrganizations[0]),
-        selectedOrgId: ref('1'),
-        selectOrganization: mockSelectOrganization,
-      }),
-    }))
   })
 
   it('should show a chip for single organization', async () => {

test/setup.ts

@@ -31,7 +31,15 @@ class LocalStorageMock {
   }
 }
 
-global.localStorage = new LocalStorageMock() as unknown as Storage
+// jsdom defines localStorage as a getter-only accessor on the window object, so a
+// plain assignment throws ("Cannot set property localStorage ... which has only a
+// getter") under vitest 5, which no longer shadows it with a writable global.
+// defineProperty replaces the accessor outright and works on both.
+Object.defineProperty(globalThis, 'localStorage', {
+  value: new LocalStorageMock() as unknown as Storage,
+  writable: true,
+  configurable: true,
+})
 
 // Make Vue composables globally available
 global.ref = Vue.ref