fix(openai): support streaming image relay and image edit for images API (#4608)

* fix(openai): support streaming image relay

* fix(openai): keep image edit multipart body reusable

* test(openai): cover image stream usage details

* test(openai): cover image edit fallback stream field

* fix(openai): wrap image json fallback as stream

* fix(relay): support OpenAI image streaming

* fix(openai): record image stream upstream error events

* fix(openai): harden image stream relay

* fix(openai): return image JSON errors

* fix(relay): reset stream status per scanner run

* fix(relay): drop upstream credit passthrough

* fix(openai): keep image errors minimal

* fix(openai): keep image error status from response

---------

Co-authored-by: CaIon <i@caion.me>

relay/helper/valid_request.go

@@ -4,6 +4,8 @@ import (
 	"errors"
 	"fmt"
 	"math"
+	"net/url"
+	"strconv"
 	"strings"
 
 	"github.com/QuantumNous/new-api/common"
@@ -144,16 +146,25 @@ func GetAndValidOpenAIImageRequest(c *gin.Context, relayMode int) (*dto.ImageReq
 	switch relayMode {
 	case relayconstant.RelayModeImagesEdits:
 		if strings.Contains(c.Request.Header.Get("Content-Type"), "multipart/form-data") {
-			_, err := c.MultipartForm()
+			form, err := common.ParseMultipartFormReusable(c)
 			if err != nil {
 				return nil, fmt.Errorf("failed to parse image edit form request: %w", err)
 			}
-			formData := c.Request.PostForm
+			formData := url.Values(form.Value)
+			c.Request.MultipartForm = form
+			c.Request.PostForm = formData
 			imageRequest.Prompt = formData.Get("prompt")
 			imageRequest.Model = formData.Get("model")
 			imageRequest.N = common.GetPointer(uint(common.String2Int(formData.Get("n"))))
 			imageRequest.Quality = formData.Get("quality")
 			imageRequest.Size = formData.Get("size")
+			if streamValue := strings.TrimSpace(formData.Get("stream")); streamValue != "" {
+				stream, err := strconv.ParseBool(streamValue)
+				if err != nil {
+					return nil, fmt.Errorf("invalid stream value: %w", err)
+				}
+				imageRequest.Stream = stream
+			}
 			if imageValue := formData.Get("image"); imageValue != "" {
 				imageRequest.Image, _ = common.Marshal(imageValue)
 			}