enhance rag retrieval + summary

README.md

@@ -43,18 +43,25 @@ graph TD
     end
 
     subgraph "Retrieval Pipeline (per chat query)"
+        RP0["Query expansion\n(QueryExpansionService)\nlay → clinical terms"]
         RP1["Text chunk search (topK=5)"]
         RP2["Figure caption search (topK=3)"]
-        RP3["Expand chunks → full section text"]
+        RP3["Expand chunks → ±1-page section text"]
         RP4["Fetch linked figures (chunk_figure_ref)"]
         RP5["Merge + deduplicate figures"]
-        RP6["Build LLM prompt + call"]
+        RP6["Build labelled prompt\n[S1],[F1]… tags"]
+        RP7["LLM chat call"]
+        RP8["Citation validation\n(CitationValidatorService)\nstrip hallucinated refs"]
+        RP0 --> RP1
+        RP0 --> RP2
         RP1 --> RP3
         RP1 --> RP4
         RP2 --> RP5
         RP4 --> RP5
         RP3 --> RP6
         RP5 --> RP6
+        RP6 --> RP7
+        RP7 --> RP8
     end
 ```