EFS Persistent Storage Integration for ECS Fargate Tasks

Act as a Cloud Storage Architect. Detail the highly specific, technical steps required to seamlessly mount an elastic, persistent Amazon EFS file system identified by [FILE_SYSTEM_ID] directly into an ephemeral ECS Fargate task. To enforce strict security and directory-level isolation, you must configure the mount utilizing a dedicated EFS [ACCESS_POINT_ID]. Provide the exact, flawless JSON payload required for the task definition's `volumes` and `containerDefinitions.mountPoints` arrays, targeting the internal [MOUNT_DIRECTORY]. Furthermore, explicitly output the [IAM_POLICY_NAME] IAM role permissions (e.g., `elasticfilesystem:ClientMount`, `ClientWrite`) absolutely required for the Fargate task execution role to physically perform network read/write operations against the NFS endpoint.