Delphi Generic Containers Reach Production Maturity with var Write-Back Support

Delphi v2.15.0 introduces fully functional generic containers (TDictionary and TList) with proper var parameter write-back, enabling realistic APIs like TryGetValue that production services depend on. This addresses a critical gap preventing Delphi from handling real-world patterns for caches, registries, and JSON maps. The release establishes the foundation for enterprise CRUD services and frameworks like Horse.