modernize

name	modernize
description	Convert R code to modern tidyverse style

Refactor the given R script to modern tidyverse conventions:

• Use the native pipe |> instead of %>% or nested calls
• Replace $ column access with dplyr::pull() or tidy eval
• Replace for loops with purrr::map() or vectorized alternatives
• Use read_csv() instead of read.csv()
• Use tibble() instead of data.frame()
• Use snake_case for all variable and function names
• Use .by argument in summarise()/mutate() instead of group_by() |> ... |> ungroup()
• Add library() calls at the top for any new packages

Preserve the original logic. Add comments where the refactored version behaves differently (e.g., stringsAsFactors defaults).