Write Widget and BLoC Unit Tests for Admin Portal

Use the bloc_test package's blocTest() function — it handles setUp, tearDown, and assertion boilerplate cleanly. For widget tests, create a helper buildTestWidget(Widget child, {AdminPortalBloc? bloc}) that wraps with MaterialApp + BlocProvider to reduce repetition. Mock Supabase by injecting a mock AdminRepository into the BLoC constructor rather than mocking Supabase directly — this keeps tests layer-appropriate.

For the RoleAssignmentPanel confirmation dialog, use tester.tap() to trigger the dialog and then tester.tap(find.text('Confirm')) to confirm — ensure pumpAndSettle() after each interaction. For pagination tests, verify both the emitted state's currentPage and the rendered widget's page indicator text. Coverage gaps are most common in error branches — explicitly test every catch block by having mock repositories throw exceptions. Run `flutter test --coverage && genhtml coverage/lcov.info -o coverage/html` locally to inspect uncovered lines before submitting.

This task IS the testing task. Tests must include: (1) BLoC unit tests using bloc_test's blocTest() helper with act/expect pattern for every event type; (2) Widget tests using WidgetTester with pumpWidget wrapping widgets in BlocProvider(create: (_) => mockBloc); (3) Golden tests optional but encouraged for AdminDashboardScreen to catch regressions; (4) Use whenListen() from bloc_test to emit sequences of states and verify widget rebuilds; (5) Coverage report generated via `flutter test --coverage` and lcov; (6) Edge case tests: empty data sets, null values in optional fields, network error states, maximum pagination boundary.