- Modified the `_exec` method in `ShellFileOperations` to accept `stdin_data`, allowing large content to be piped directly to commands, bypassing ARG_MAX limitations.
- Updated the `execute` method in various environment classes (`_LocalEnvironment`, `_SingularityEnvironment`, `_SSHEnvironment`, `_DockerEnvironment`) to support `stdin_data`, improving command execution flexibility.
- Removed the unique marker generation for heredoc in favor of direct stdin piping, simplifying file writing operations and enhancing performance for large files.