Add duplicate detection to banner recording to prevent multiple entries
for the same banner ID in recent history. This prevents duplicate history
entries when pages refresh or banners are shown multiple times.
- Check if banner ID already exists in recentHistory before adding
- Return early if duplicate found to prevent adding same banner multiple times
- Add comprehensive tests for banner history functionality including:
- Adding new banners to history
- Preventing duplicate entries
- Handling multiple different banners
- Clear history between tests to ensure test isolation
- Remove legacy community support banner tracking variables and logic
- Simplify banner dismissal handling by checking dismissal state before marking
- Replace timer-based community support banner with immediate registration
- Clean up unused constants and legacy storage keys
- Add comprehensive test suite with mocked dependencies
- Improve code maintainability and test coverage
