fix: forget to take reference/prompt in pipeline final (#17032)

### Summary

As title:

fixed: 
<img width="3710" height="2036"
alt="img_v3_0213m_b4b79593-43cd-4dd3-a1dc-ce8a6b34645g"
src="https://github.com/user-attachments/assets/5045f2d2-cef1-4f91-9d3b-c79da78a6716"
/>

internal/router/router.go

@@ -17,9 +17,10 @@
 package router
 
 import (
-	"github.com/gin-gonic/gin"
 	"ragflow/internal/common"
 	"ragflow/internal/handler"
+
+	"github.com/gin-gonic/gin"
 )
 
 type Router struct {

internal/service/chat_session.go

@@ -1609,7 +1609,15 @@ func (s *ChatSessionService) ChatCompletions(
 						}
 						sendOrCancel(fmt.Sprintf("data:%s\n\n", sseMarshalChunk(sanitizeJSONFloats(ans).(map[string]interface{}), chatID)))
 					} else {
-						ans := s.structureAnswer(session, "", messageID, sessionID, reference)
+						ans := s.structureAnswer(session, result.Answer, messageID, sessionID, reference)
+						if result.Reference != nil {
+							ans["reference"] = result.Reference
+						}
+						ans["audio_binary"] = result.AudioBinary
+						ans["prompt"] = result.Prompt
+						if result.CreatedAt != 0 {
+							ans["created_at"] = result.CreatedAt
+						}
 						ans["final"] = true
 						if chatID != "" {
 							ans["chat_id"] = chatID
@@ -1779,7 +1787,6 @@ func (s *ChatSessionService) buildDefaultCompletionDialog(tenantID string) *enti
 	}
 }
 
-// createSessionForCompletion mirrors Python _create_session_for_completion.
 func (s *ChatSessionService) createSessionForCompletion(chatID string, dialog *entity.Chat, userID string) (*entity.ChatSession, error) {
 	newID := utility.GenerateUUID()
 	name := "New session"

internal/service/chat_session_test.go

@@ -903,6 +903,123 @@ func TestChatCompletionsPassesRequestUserIDToPipeline(t *testing.T) {
 	}
 }
 
+func TestChatCompletionsStreamFinalCarriesDecoratedReference(t *testing.T) {
+	store := newFakeSessionStore()
+	store.sessions["session-1"] = &entity.ChatSession{
+		ID:        "session-1",
+		DialogID:  "dialog-1",
+		Message:   json.RawMessage(`[{"role":"assistant","content":"Welcome!"}]`),
+		Reference: json.RawMessage(`[]`),
+	}
+	store.dialogs["dialog-1"] = &entity.Chat{
+		ID:         "dialog-1",
+		TenantID:   "tenant-owner",
+		LLMID:      "chat@factory",
+		LLMSetting: entity.JSONMap{},
+		PromptConfig: entity.JSONMap{
+			"parameters": []interface{}{},
+		},
+	}
+	store.dialogExists["tenant-owner|dialog-1"] = true
+
+	finalReference := map[string]interface{}{
+		"chunks": []map[string]interface{}{
+			{
+				"id":            "chunk-1",
+				"content":       "Marigold is a depth-estimation model.",
+				"document_id":   "doc-1",
+				"document_name": "paper.pdf",
+			},
+		},
+		"doc_aggs": []interface{}{
+			map[string]interface{}{"doc_id": "doc-1", "doc_name": "paper.pdf", "count": 1},
+		},
+		"total": 1,
+	}
+	pipeline := &fakePipeline{
+		resultChan: makeResultChan(
+			AsyncChatResult{Answer: "Marigold", Reference: map[string]interface{}{"chunks": []interface{}{}}, Final: false},
+			AsyncChatResult{
+				Answer:    "Marigold is a depth-estimation model. [ID:0]",
+				Reference: finalReference,
+				Prompt:    "### Query: what is marigold",
+				CreatedAt: 123,
+				Final:     true,
+			},
+		),
+	}
+
+	svc := &ChatSessionService{
+		chatSessionDAO: store,
+		userTenantDAO:  &fakeTenantStore{tenantIDs: []string{"tenant-owner"}},
+		pipeline:       pipeline,
+	}
+
+	streamChan := make(chan string, 8)
+	_, err := svc.ChatCompletions(
+		context.Background(),
+		"user-1",
+		"dialog-1",
+		"session-1",
+		[]map[string]interface{}{{"role": "user", "content": "what is marigold"}},
+		"",
+		nil,
+		"",
+		nil,
+		nil,
+		false,
+		false,
+		true,
+		streamChan,
+	)
+	if err != nil {
+		t.Fatalf("ChatCompletions failed: %v", err)
+	}
+
+	var finalData map[string]interface{}
+	eventCount := len(streamChan)
+	for i := 0; i < eventCount; i++ {
+		event := <-streamChan
+		payload := strings.TrimSpace(strings.TrimPrefix(strings.TrimSpace(event), "data:"))
+		var wrapper map[string]interface{}
+		if err := json.Unmarshal([]byte(payload), &wrapper); err != nil {
+			t.Fatalf("failed to parse SSE payload %q: %v", payload, err)
+		}
+		data, ok := wrapper["data"].(map[string]interface{})
+		if !ok {
+			continue
+		}
+		if final, _ := data["final"].(bool); final {
+			finalData = data
+			break
+		}
+	}
+	if finalData == nil {
+		t.Fatal("missing final SSE data")
+	}
+	if got := finalData["answer"]; got != "Marigold is a depth-estimation model. [ID:0]" {
+		t.Fatalf("final answer = %v", got)
+	}
+	if got := finalData["prompt"]; got != "### Query: what is marigold" {
+		t.Fatalf("final prompt = %v", got)
+	}
+	ref, ok := finalData["reference"].(map[string]interface{})
+	if !ok {
+		t.Fatalf("final reference = %#v", finalData["reference"])
+	}
+	chunks, ok := ref["chunks"].([]interface{})
+	if !ok || len(chunks) != 1 {
+		t.Fatalf("final reference chunks = %#v", ref["chunks"])
+	}
+	docAggs, ok := ref["doc_aggs"].([]interface{})
+	if !ok || len(docAggs) != 1 {
+		t.Fatalf("final reference doc_aggs = %#v", ref["doc_aggs"])
+	}
+	if got := ref["total"]; got != float64(1) {
+		t.Fatalf("final reference total = %v", got)
+	}
+}
+
 func TestCompletion_EmptyMessages(t *testing.T) {
 	svc := &ChatSessionService{
 		chatSessionDAO: &fakeSessionStore{},