- 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