GHSA-6x2m-p4xp-wg22: Network-AI: EnvironmentManager.backup() follows symlinked directories and copies files outside the environment root into backups

EnvironmentManager.backup() recursively collects files using _collectBackupFiles(). _collectBackupFiles() uses statSync(full), which follows symlinks. If data/<env> contains a symlink to a directory outside the environment root, backup recursion follows the symlink and copies external files into data/<env>/.backups/<backupId>/.

An attacker who can place a symlink under the environment data directory can cause backup operations to disclose files outside the environment root into backup artifacts. Confirmed in Network-AI 5.12.1.