Add type parameters to vi.fn() mocks for oxlint 1.60 vitest rule

oxlint 1.60 enables vitest/require-mock-type-parameters by default,
which requires explicit type parameters on all vi.fn() calls.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/views/__tests__/EventDetailView.spec.ts

@@ -6,26 +6,26 @@ import { api } from '@/api/client'
 
 vi.mock('@/api/client', () => ({
   api: {
-    GET: vi.fn(),
-    POST: vi.fn(),
+    GET: vi.fn<typeof api.GET>(),
+    POST: vi.fn<typeof api.POST>(),
   },
 }))
 
-const mockSaveRsvp = vi.fn()
-const mockGetRsvp = vi.fn()
-const mockGetOrganizerToken = vi.fn()
-const mockSaveWatch = vi.fn()
-const mockIsStored = vi.fn()
-const mockRemoveEvent = vi.fn()
+const mockSaveRsvp = vi.fn<(...args: unknown[]) => void>()
+const mockGetRsvp = vi.fn<(eventToken: string) => { rsvpToken: string; rsvpName: string } | undefined>()
+const mockGetOrganizerToken = vi.fn<(eventToken: string) => string | undefined>()
+const mockSaveWatch = vi.fn<(...args: unknown[]) => void>()
+const mockIsStored = vi.fn<(eventToken: string) => boolean>()
+const mockRemoveEvent = vi.fn<(eventToken: string) => void>()
 
 vi.mock('@/composables/useEventStorage', () => ({
-  useEventStorage: vi.fn(() => ({
-    saveCreatedEvent: vi.fn(),
-    getStoredEvents: vi.fn(() => []),
+  useEventStorage: vi.fn<() => unknown>(() => ({
+    saveCreatedEvent: vi.fn<() => void>(),
+    getStoredEvents: vi.fn<() => unknown[]>(() => []),
     getOrganizerToken: mockGetOrganizerToken,
     saveRsvp: mockSaveRsvp,
     getRsvp: mockGetRsvp,
-    removeRsvp: vi.fn(),
+    removeRsvp: vi.fn<() => void>(),
     saveWatch: mockSaveWatch,
     isStored: mockIsStored,
     removeEvent: mockRemoveEvent,