Questions re: anyOf/allOf/oneOf, and one more thing

### Question

I'm sure there are details I'm unaware of that impact these things, so forgive me if this has been discussed before. I have a few questions/thoughts regarding `anyOf`/`allOf`/`oneOf`:

- Could `oneOf` be translated to an enum with associated values of the possible options?

- For `anyOf`/`oneOf` where the only options are `"null"` and some `$ref`, could it be translated to an optional instance of that type? Because as of now, it's this:
```swift
struct itemPayload: Codable, Hashable, Sendable {
var value1: OpenAPIRuntime.OpenAPIValueContainer?
var value2: Components.Schemas.NamedAPIResource?
}
```
from this:
```json
"item": {
"anyOf": [
{
"type": "null"
},
{
"$ref": "./NamedAPIResource.json"
}
]
}
```
when it would ideally just be:
```swift
typealias itemPayload: Components.Schemas.NamedAPIResource?
```

Separately, is it possible to set the configuration so the generated types from `components/schemas` are `public`, but the initializers and underlying stuff is `internal`? Or would I just have to do 2 separate targets that generate the types and clients separately, then I combine them for public-facing stuff in a 3rd target?

No file, test, or entry point is named. Start by tracing how the generator maps anyOf/allOf/oneOf and how access control is configured for generated component schemas; done would mean a maintainer decision on optional/reference and enum representations plus public schema and internal initializer support, or documented constraints.

Written by the indexing model from the issue text.