Refactor benchmark suite to use enums for config
Replaced string parameters for layer, opMode, and serializerMode with strongly-typed enums (BenchmarkLayer, BenchmarkOpMode, SerializerSelectionMode) across BenchmarkLoop, Menu, and Program. Updated CLI parsing and menu logic to use Enum.TryParse and return enums. Added XML docs for new enums. Improves type safety, code clarity, and maintainability.
Refactor benchmarks to use typed enums for engine/mode
Replaced string-based identifiers for serializer engine, I/O mode, and dispatch mode with strongly-typed enums (BenchmarkEngine, BenchmarkIoMode, BenchmarkDispatchMode). Added BenchmarkEnums.cs with ToDisplay() helpers for consistent output. Updated all benchmark implementations, DTOs, and output logic to use enums. Removed obsolete string constants from Configuration.cs. Merged allocation measurement methods in BenchmarkLoop.cs for clarity. Improves type safety, maintainability, and output consistency.