Implement OpenAPI 3.2.0 server name field with backward compatibility

[Copilot]

• Implement OpenAPI 3.2.0 server name field with backward compatibility
• Add comprehensive test coverage for server name serialization/deserialization
• Update benchmark results for EmptyModels

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Server - new name field</issue_title>
<issue_description>OAI 3.2.0 defines a new server name field (string?)

We should add this new field to the model, and implement serialization/deserialization.

When serializing to OpenAPI 3.1.0, we should add an x-oai- prefix to make it an extension</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes#16

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[baywet]

@copilot run the following commands cd performance/benchmark && dotnet run -c Release EmptyModels and commit the results, do nothing else

[Copilot]

@copilot run the following commands cd performance/benchmark && dotnet run -c Release EmptyModels and commit the results, do nothing else

Benchmark results updated in commit d964404.