CSV cleanup
Use this when the user wants to tidy CSV data.
Steps
- Detect the delimiter (comma, tab, or semicolon) from the header row.
- Trim leading and trailing whitespace from every cell.
- Drop rows that are exact duplicates of an earlier row.
- Report the final row and column counts, and how many duplicates were removed.
Always show the cleaned result and a one-line summary of what changed.