fix: Read Qwen response from 'thinking' field when 'response' is empty

Qwen 3.5 with latest Ollama returns structured thinking in separate
'thinking' field, leaving 'response' empty. Now checks both fields.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend-compliance/compliance/services/rag_document_checker.py

@@ -205,7 +205,11 @@ async def _verify_control_with_llm(
         if resp.status_code != 200:
             return None
 
-        raw = resp.json().get("response", "").strip()
+        data = resp.json()
+        # Qwen 3.5 may return content in 'response' or 'thinking' field
+        raw = data.get("response", "").strip()
+        if not raw:
+            raw = data.get("thinking", "").strip()
         # Strip think tags if present
         raw = re.sub(r"<think>.*?</think>", "", raw, flags=re.DOTALL).strip()