Implement optional static polymorphism instead of direct inheritance from interface

[konard]

Summary

• Implements optional static polymorphism pattern for Memory classes instead of direct interface inheritance
• Creates Polymorph<TSelf, TBase...> base class that enables compile-time polymorphic behavior
• Updates all Memory classes to use the new pattern: ArrayMemory, FileArrayMemory, DirectMemoryAsArrayMemoryAdapter, HeapResizableDirectMemory, FileMappedResizableDirectMemory, TemporaryFileMappedResizableDirectMemory
• Provides self() and as<T>() methods for accessing the derived type without runtime overhead

Implementation Details

• Polymorph class: Template base class that inherits from multiple base classes and provides static polymorphism methods
• Static polymorphism methods:
  • self() - returns reference to the derived type
  • as<T>() - allows casting to specific type at compile time
• Zero runtime overhead: All polymorphic behavior is resolved at compile time
• Backward compatibility: Maintains all existing functionality while adding static polymorphism capabilities

Example Usage

ArrayMemory<int> arrayMem(10);
auto& selfRef = arrayMem.self();           // Gets ArrayMemory<int>&
auto& asRef = arrayMem.as<ArrayMemory<int>>(); // Explicit type casting

Test plan

• All modified classes compile successfully with C++20
• Static polymorphism methods (self(), as<T>()) work correctly
• Maintains compatibility with existing interface contracts
• No runtime performance impact (compile-time polymorphism only)
• All inheritance relationships preserved with new Polymorph pattern

🤖 Generated with Claude Code

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Resolves #75