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>

dto/openai_image.go

@@ -26,11 +26,11 @@ type ImageRequest struct {
 	OutputFormat      json.RawMessage `json:"output_format,omitempty"`
 	OutputCompression json.RawMessage `json:"output_compression,omitempty"`
 	PartialImages     json.RawMessage `json:"partial_images,omitempty"`
-	// Stream            bool            `json:"stream,omitempty"`
-	Images        json.RawMessage `json:"images,omitempty"`
-	Mask          json.RawMessage `json:"mask,omitempty"`
-	InputFidelity json.RawMessage `json:"input_fidelity,omitempty"`
-	Watermark     *bool           `json:"watermark,omitempty"`
+	Stream            bool            `json:"stream,omitempty"`
+	Images            json.RawMessage `json:"images,omitempty"`
+	Mask              json.RawMessage `json:"mask,omitempty"`
+	InputFidelity     json.RawMessage `json:"input_fidelity,omitempty"`
+	Watermark         *bool           `json:"watermark,omitempty"`
 	// zhipu 4v
 	WatermarkEnabled json.RawMessage `json:"watermark_enabled,omitempty"`
 	UserId           json.RawMessage `json:"user_id,omitempty"`
@@ -163,7 +163,7 @@ func (i *ImageRequest) GetTokenCountMeta() *types.TokenCountMeta {
 }
 
 func (i *ImageRequest) IsStream(c *gin.Context) bool {
-	return false
+	return i.Stream
 }
 
 func (i *ImageRequest) SetModelName(modelName string) {

dto/openai_image_test.go

@@ -0,0 +1,16 @@
+package dto
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// TestImageRequestStreamJSON verifies that image requests preserve stream=true.
+func TestImageRequestStreamJSON(t *testing.T) {
+	var req ImageRequest
+	require.NoError(t, req.UnmarshalJSON([]byte(`{"model":"gpt-image-1","prompt":"draw a cat","stream":true}`)))
+
+	require.True(t, req.Stream)
+	require.True(t, req.IsStream(nil))
+}