fix: increase K in chat endpoint to 10

src/api/v1/chat.py

@@ -189,9 +189,12 @@ async def chat_stream(request: ChatRequest, db: AsyncSession = Depends(get_db)):
         sources: List[Dict[str, Any]] = []
 
         if intent_result is None:
-            # Step 2: Launch retrieval and history loading in parallel, then run orchestrator
+            # Step 2: Launch retrieval and history loading in parallel, then run orchestrator.
+            # k=10 (not the wrapper default of 5) so the merged top-k spans more
+            # tables — db_executor's FK expansion is one-hop and cannot bridge
+            # 2-hop gaps (e.g. customers -> order_items -> products) on its own.
             retrieval_task = asyncio.create_task(
-                retriever.retrieve(request.message, request.user_id, db)
+                retriever.retrieve(request.message, request.user_id, db, k=10)
             )
             history_task = asyncio.create_task(
                 load_history(db, request.room_id, limit=6)  # 6 msgs (3 pairs) for orchestrator
@@ -219,6 +222,7 @@ async def chat_stream(request: ChatRequest, db: AsyncSession = Depends(get_db)):
                         query=search_query,
                         user_id=request.user_id,
                         db=db,
+                        k=10,
                         source_hint=intent_result.get("source_hint", "both"),
                     )
                 else: