test(communities): add E2E tests and update service mocks
E2E Tests (3 new test cases):
- Block via XRPC endpoint: Full flow from HTTP → PDS → Jetstream → AppView
- Unblock via XRPC endpoint: Complete unblock flow with DELETE event
- Block fails without authentication: Validates auth requirement (401)
Each E2E test verifies:
✓ XRPC endpoint responds correctly
✓ Record created/deleted on PDS
✓ Jetstream consumer indexes event
✓ AppView database state updated
Unit Test Updates:
- Added 6 mock methods to mockCommunityRepo for blocking operations
- Ensures service layer tests compile and pass
All tests follow existing E2E patterns (subscribe/unsubscribe) for
consistency.