Tagging (#4426)

### What problem does this PR solve?

#4367

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

api/apps/sdk/dify_retrieval.py

@@ -16,6 +16,7 @@
 from flask import request, jsonify
 
 from api.db import LLMType, ParserType
+from api.db.services.dialog_service import label_question
 from api.db.services.knowledgebase_service import KnowledgebaseService
 from api.db.services.llm_service import LLMBundle
 from api import settings
@@ -54,7 +55,8 @@ def retrieval(tenant_id):
             page_size=top,
             similarity_threshold=similarity_threshold,
             vector_similarity_weight=0.3,
-            top=top
+            top=top,
+            rank_feature=label_question(question, [kb])
         )
         records = []
         for c in ranks["chunks"]: