Updated RecentReceiverSuggestionDto to use `init` properties, adding immutability and a new `LastUsedAt` field. Refactored ReadRecentReceiverSuggestionsQueryHandler to simplify query logic, remove `IMapper` dependency, and improve determinism in results. Introduced tie-breaking for duplicate timestamps and optimized ordering by `LastUsedAt` and `EmailAddress`. Removed redundant `Include` and mapping steps for clarity.