Function rotate_files 

pub fn rotate_files(
    dir: &Path,
    config: &RetentionConfig,
    dry_run: bool,
    trash_cmd: Option<&str>,
) -> Result<(usize, usize)>

Rotates files in a directory based on retention policies.

Errors

Returns an error if:

• keep_last is 0 (must be at least 1)
• The directory cannot be read
• Files cannot be moved to trash