Diff two versions of a sheet and show what changed

Compare these two versions of the same dataset: [link or tab for the old version] and [link or tab for the new version]. Match rows by [key column, e.g. ID or email]. Produce a change report with three sections: rows added (in new but not old), rows removed (in old but not new), and rows changed — for changed rows, show only the cells that differ, as old value -> new value. Ignore cosmetic differences like whitespace and capitalization unless I say otherwise. Put the report in chat with summary counts up top, and write the full detail to a new tab called Diff in the new sheet. If the key column has duplicates that make matching ambiguous, list those rows separately instead of guessing.