fix: add missing removeOnboardingFiles mock to setupTests

Author: VariableThe

src/setupTests.ts

@@ -76,6 +76,7 @@ if (typeof window !== 'undefined') {
     cancelReminders: vi.fn().mockResolvedValue(undefined),
     scheduleTimer: vi.fn().mockResolvedValue(undefined),
     cancelTimer: vi.fn().mockResolvedValue(undefined),
+    removeOnboardingFiles: vi.fn().mockResolvedValue(undefined),
   } as ElectronAPI
 }