Fix UI test failures: registration dismiss cascade, onboarding reset, test stability

- Fix registration flow dismiss cascade: chain fullScreenCover → sheet onDismiss
  so auth state is set only after all UIKit presentations are removed, preventing
  RootView from swapping LoginView→MainTabView behind a stale sheet
- Fix onboarding reset: set hasCompletedOnboarding directly instead of calling
  completeOnboarding() which has an auth guard that fails after DataManager.clear()
- Stabilize Suite1 registration tests, Suite6 task tests, Suite7 contractor tests
- Add clean-slate-per-suite via AuthenticatedUITestCase reset state
- Improve test account seeding and screen object reliability

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

iosApp/run_ui_tests.sh

@@ -67,10 +67,10 @@ PARALLEL_TESTS=(
     "-only-testing:HoneyDueUITests/NavigationCriticalPathTests"
     "-only-testing:HoneyDueUITests/SmokeTests"
     "-only-testing:HoneyDueUITests/SimpleLoginTest"
-    "-only-testing:HoneyDueUITests/Suite0_OnboardingTests"
+    "-only-testing:HoneyDueUITests/Suite0_OnboardingRebuildTests"
     "-only-testing:HoneyDueUITests/Suite1_RegistrationTests"
-    "-only-testing:HoneyDueUITests/Suite2_AuthenticationTests"
-    "-only-testing:HoneyDueUITests/Suite3_ResidenceTests"
+    "-only-testing:HoneyDueUITests/Suite2_AuthenticationRebuildTests"
+    "-only-testing:HoneyDueUITests/Suite3_ResidenceRebuildTests"
     "-only-testing:HoneyDueUITests/Suite4_ComprehensiveResidenceTests"
     "-only-testing:HoneyDueUITests/Suite5_TaskTests"
     "-only-testing:HoneyDueUITests/Suite6_ComprehensiveTaskTests"