Fix incorrect calculation of DataEditor height.

[infalmo]

No description provided.

[Copilot]

Pull Request Overview

The PR corrects the height calculation in DataEditor by summing each row’s actual height instead of using an averaged value.

• Removed sampling-based average and floor division.
• Updated the else branch to accumulate total header height plus the height of each row.
• Preserved scrollbar width addition.

Comments suppressed due to low confidence (2)

packages/core/src/data-editor/data-editor.tsx:3992

• This new dynamic row height summation logic should be covered by unit tests to verify correct height calculation for various rowHeight callback implementations.

h = totalHeaderHeight;

packages/core/src/data-editor/data-editor.tsx:3993

• Iterating over every row to sum heights may introduce performance bottlenecks for large data sets. Consider memoizing row heights or computing cumulative heights outside of render to avoid repeated work.

for (let i = 0; i < rowsCountWithTrailingRow; i++) {

[BrianHung]

I believe sampling only 10 rows as opposed to all rows was an intentional performance optimization, as summing heights for thousands or millions of rows is an issue.