fix: Disable Qwen thinking mode for RAG checks (/no_think prefix)

Qwen 3.5 uses all tokens for thinking, leaving response empty.
Using /no_think prefix to get direct JSON output.

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

backend-compliance/compliance/services/rag_document_checker.py

@@ -197,9 +197,9 @@ async def _verify_control_with_llm(
         async with httpx.AsyncClient(timeout=120.0) as client:
             resp = await client.post(f"{OLLAMA_URL}/api/generate", json={
                 "model": OLLAMA_MODEL,
-                "prompt": prompt,
+                "prompt": "/no_think\n" + prompt,  # Disable thinking mode
                 "stream": False,
-                "options": {"num_predict": 200},  # Limit response length
+                "options": {"num_predict": 300},
             })
 
         if resp.status_code != 200: