Clean and Standardize Multiple CSV Files
This section reads several CSV files and applies a simple cleaning step to each one before saving them later. The cleaning differs by file: one branch standardizes text across multiple columns, another keeps only the needed columns, fills missing values, and converts numeric fields from decimal to integer, another just fills in missing values, and another performs a text transformation on one column. Overall, the goal is to make each dataset more complete, consistent, and ready for further use.
