fix(library): enforce spec-compliant $ref serialization; add Extensions support for schema references in v3.1/v3.2#2782

baywet merged 9 commits intomainmicrosoft/OpenAPI.NET:mainfrom

copilot/fix-openapi-schema-reference-descriptionmicrosoft/OpenAPI.NET:copilot/fix-openapi-schema-reference-descriptionCopy head branch name to clipboard