fix(lead-stage): remove duplicate merged_product_ids calculation

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/agent/lead_stage_agent/graph.py

@@ -640,10 +640,7 @@ class LeadStageGraph:
 
         # Ensure product_ids covers every SKU mentioned in ai_response (deterministic safeguard)
         from_text = _extract_skus_from_text(output.ai_response)
-        merged_product_ids = _dedupe_preserve_order((output.product_ids or []) + from_text)
-
-        # Extract insight - handle both dict and object cases
-        merged_product_ids = _dedupe_preserve_order((output.product_ids or []) + from_text)
+        merged_product_ids = _dedupe_preserve_order((getattr(output, "product_ids", []) or []) + from_text)
 
         # Extract insight - handle both dict and object cases
         insight_raw = getattr(output, "user_insight", None)