Improve JsonSchema

[Joy-less]

The JsonSchema generator introduced in #150 is really useful. However, it provides an incorrect output for pretty basic cases:

public class Dialog {
    public DialogLine[] DialogLines { get; set; } = []; // The LLM generates any object, ignoring the DialogLine schema.
}
public class DialogLine {
    public string Name { get; set; }
    public string Speech { get; set; }
}

Consider looking into https://github.com/tryAGI/CSharpToJsonSchema, which successfully converts the above to a schema.