fix: Address Bugbot feedback on submit_feedback and duplicated logic

1. submit_feedback now checks response.ok before parsing JSON
2. verify_before_trade uses approved variable instead of duplicating logic
3. Consistent error handling across all methods

Author: drkavner

agents/connectors/cogdx.py

@@ -203,7 +203,8 @@ def verify_before_trade(
 
         approved = validity >= min_validity and len(flaws) == 0
 
-        if validity >= min_validity and len(flaws) == 0:
+        # Use approved variable to avoid duplicated logic
+        if approved:
             recommendation = "proceed"
         elif validity >= 0.5:
             recommendation = "review"
@@ -302,6 +303,11 @@ def submit_feedback(
                 timeout=30
             )
 
+            if response.status_code == 402:
+                return {"error": "payment_required", "received": False}
+            if not response.ok:
+                return {"error": f"http_{response.status_code}", "received": False}
+            
             return response.json()
 
         except Exception as e: