Non-breaking reafactoring changes, with one bug fixed

[ReneDuris]

This PR includes several improvements with no breaking changes:

Refactorings:
Merged duplicate guard utility functions
Added runtime type assertions in type system constructors for better error detection
Split generic types into separate files (genericOption.ts, genericList.ts)
Refactored ArgSerializer by extracting complex recursive logic into dedicated helper classes (BufferReader, BufferWriter, TypeValueReader, TypeValueWriter)

Bug Fix:
Fixed OptionValue type construction in option codec - was passing inner type instead of wrapped OptionType (bug exposed by new type assertions)

// BEFORE (incorrect):
decodeTopLevel(buffer: Buffer, type: Type): OptionValue {
    // type is U32Type (inner type), not OptionType!
    return new OptionValue(type, decoded);  // ❌ Wrong type
}

// AFTER (correct):
decodeTopLevel(buffer: Buffer, type: Type): OptionValue {
    const optionType = new OptionType(type);  // ✅ Wrap inner type
    return new OptionValue(optionType, decoded);  // ✅ Correct type
}

All changes maintain full backward compatibility. All tests passing.