Use Case:
As a user of a large workboard, I would like the ability to click, drag and scroll to move a task between long, short and distant columns so that I can move a task from one exact location to another exact location.

Acceptance Criteria:

Extending the "drag target" of each column to match the longest column on the board.

nice to have:

Click and drag a task to the left or right edge of the browser starts a scroll in that direction.
We want to acknowledge that this has been discussed. We would like to focus the conversation on the use case above.

This is a longer conversation with several options. I would still like to advocate for the use case above.
T5240

This mixes the topics of column headers and side scrolling. I think they should be discussed separately.
T5002

This is also tracked in the wikimedia phabricator task:
https://phabricator.wikimedia.org/T119227