Function process_batch 

pub fn process_batch<I, F>(
    processor: &MarkdownProcessor,
    files: I,
    read_file_fn: F,
) -> Vec<(String, Result<MarkdownResult, String>)>
where
    I: Iterator<Item = PathBuf>,
    F: Fn(&Path) -> Result<String, Error>,

Process a batch of markdown files with consistent error handling.

This function processes multiple markdown files using the same processor configuration, collecting results and handling errors gracefully.

Arguments

• processor - The configured markdown processor
• files - Iterator of file paths to process
• read_file_fn - Function to read file content from path

Returns

Vector of tuples containing (file_path, processing_result)