fix(memory): add coalesce defaults for activation_value and related node properties

- Add coalesce fallbacks for importance_score, activation_value, and
access_count in statement, entity, weak entity, strong entity, and
memory summary MERGE queries to prevent null values on new nodes
- Set activation_value default to coalesce(importance_score, 0.5) for
consistency with the forgetting/activation scoring logic
- Suppress Neo4j UNRECOGNIZED property key notifications in driver init
since missing keys like last_access_time and activation_value are
expected for newly created nodes

api/app/repositories/neo4j/neo4j_connector.py

@@ -9,12 +9,15 @@ Classes:
 """
 
 from typing import Any, List, Dict
+import logging
 
 from neo4j import AsyncGraphDatabase, basic_auth
 from neo4j.time import DateTime as Neo4jDateTime, Date as Neo4jDate, Time as Neo4jTime, Duration as Neo4jDuration
 
 from app.core.config import settings
 
+logger = logging.getLogger(__name__)
+
 
 def _convert_neo4j_types(value: Any) -> Any:
     """递归将 neo4j 原生时间类型转为 Python 原生类型 / ISO 字符串，确保可被 json.dumps 序列化。"""
@@ -67,7 +70,12 @@ class Neo4jConnector:
             )
         self.driver = AsyncGraphDatabase.driver(
             uri,
-            auth=basic_auth(username, password)
+            auth=basic_auth(username, password),
+            # 抑制属性键不存在的 UNRECOGNIZED 分类通知警告（如 01N52）
+            # last_access_time 等属性在节点被检索命中后才写入，
+            # activation_value 在新节点创建后可能尚未被计算，
+            # 全新数据库或清空数据后这些属性键不存在是正常业务行为
+            notifications_disabled_classifications=["UNRECOGNIZED"],
         )
 
     async def close(self):