Pass ContentHints format through to generated OpenAPI schema

[SimonAllmendinger]

Problem

Even if ContentHints carries a format value (see companion PR oatpp/oatpp#…), the generator currently ignores it. The generated OpenAPI 3.0 spec never contains a format field on response or request body schemas, making it impossible to distinguish string from string + format: binary or string + format: byte.

This matters for client code generators: without format: binary, tools like NSwag and OpenAPI Generator produce string return types for endpoints that return raw binary data (e.g. JPEG images), corrupting the payload through text encoding.

Changes

Two small additions in Generator.cpp:

• generateResponses() — after generateSchemaForType(), the response schema's format is set from hint.second.format if present.
• generateRequestBody() — same logic for hint.format on consume schemas.

Both additions are guarded by a null check, so existing endpoints without a format hint are completely unaffected.

Companion PR

Depends on oatpp/oatpp#… which adds the format field to ContentHints and the corresponding addResponse/addConsumes overloads.

Result

With both PRs applied, this endpoint annotation:

info->addResponse<String>(Status::CODE_200, "image/jpeg",
                          "Raw JPEG image bytes", "binary");

produces:

"200": {
  "content": {
    "image/jpeg": {
      "schema": { "type": "string", "format": "binary" }
    }
  }
}