doc-service: parse fact_value_json string in doc context lookup

gateway-bot/services/doc_service.py

@@ -11,6 +11,7 @@ This service can be used by:
 import os
 import logging
 import hashlib
+import json
 from typing import Optional, Dict, Any, List
 from pydantic import BaseModel
 from datetime import datetime
@@ -160,6 +161,12 @@ class DocumentService:
             if fact and fact.get("fact_value_json"):
                 logger.debug(f"Retrieved doc context for session {session_id}")
                 ctx_data = fact.get("fact_value_json")
+                if isinstance(ctx_data, str):
+                    try:
+                        ctx_data = json.loads(ctx_data)
+                    except Exception:
+                        logger.warning("doc_context fact_value_json is not valid JSON string")
+                        return None
                 return DocContext(**ctx_data)
             
             return None