fix: Correct Ollama model name + strict blank-line heading detection

1. LLM model: qwen3:32b → qwen3.5:35b-a3b (actual model on Mac Mini)
2. Section splitter: headings MUST be preceded by a blank line.
   This prevents cookie table entries ("Funktionale Cookies",
   "Session Cookies") from splitting the cookie section.

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

backend-compliance/compliance/services/doc_checks/llm_verify.py

@@ -15,7 +15,7 @@ import httpx
 logger = logging.getLogger(__name__)
 
 OLLAMA_URL = os.getenv("OLLAMA_URL", "http://host.docker.internal:11434")
-OLLAMA_MODEL = os.getenv("OLLAMA_VERIFY_MODEL", "qwen3:32b")
+OLLAMA_MODEL = os.getenv("OLLAMA_VERIFY_MODEL", "qwen3.5:35b-a3b")
 TIMEOUT = 30.0