Fix AI search by appending query expansions instead of replacing the original query

webapp/tipitaka-api/app/services/search_service.py

@@ -340,8 +340,14 @@ class SearchService:
                 transformed = await asyncio.wait_for(
                     self.qts.transform(corrected_q), timeout=10.0
                 )
-                fts_queries = transformed.get("fts_queries", fts_queries)
-                vector_queries = transformed.get("vector_queries", vector_queries)
+                for fq in transformed.get("fts_queries", []):
+                    fq_clean = fq.strip()
+                    if fq_clean and fq_clean not in fts_queries:
+                        fts_queries.append(fq_clean)
+                for vq in transformed.get("vector_queries", []):
+                    vq_clean = vq.strip()
+                    if vq_clean and vq_clean not in vector_queries:
+                        vector_queries.append(vq_clean)
             except asyncio.TimeoutError:
                 pass  # fallback to raw query — ไม่บล็อก search