Function with_stdin_support 

pub fn with_stdin_support<F>(file: &Path, f: F) -> Result<(), CliError>
where
    F: FnOnce(&Path) -> Result<(), CliError>,

Run a command with stdin pipe support and directory resolution.

• If file is -, buffer stdin to a tempfile.
• If file is a directory, resolve to the model file inside it (e.g., model.safetensors, *.gguf, *.apr).
• Otherwise pass the path through.