Blueprint Studio terminal command working directory not bounded to config directory

Blueprint Studio is a VS Code-like file editor for Home Assistant configuration files. Prior to 2.5.2, the legacy stateless terminal command execution path in custom_components/blueprint_studio/backend/terminal_manager.py accepted a cwd working-directory parameter and checked only whether the directory existed, without requiring it to remain inside the Home Assistant configuration directory. An administrator using the restricted terminal helper could select an existing directory outside the intended configuration boundary. Commands could then access or modify host paths permitted by the Home Assistant container and filesystem permissions, weakening the helper's expected filesystem restriction. This issue is fixed in version 2.5.2.