Add support for 4o-mini and 3o (#968)

- This adds supports, and tests, for the 3o and 4o-mini class of models

reasoning_validator.go

@@ -40,8 +40,9 @@ func NewReasoningValidator() *ReasoningValidator {
 func (v *ReasoningValidator) Validate(request ChatCompletionRequest) error {
 	o1Series := strings.HasPrefix(request.Model, "o1")
 	o3Series := strings.HasPrefix(request.Model, "o3")
+	o4Series := strings.HasPrefix(request.Model, "o4")
 
-	if !o1Series && !o3Series {
+	if !o1Series && !o3Series && !o4Series {
 		return nil
 	}