[Bug] Competency Management page: columns need a fixed height, and competency rows don't show a clickable cursor #835

Environment: Master Sandbox, https://apps.master.openedx.io/authoring/taxonomy/46/competencies

Select any competency before checking the points below, so that the right-hand course panel is shown.

1. The left column (competency tree) is shorter than the right column (course panel). Both columns should have the same height.

2. When all competencies are expanded with "Expand All", the left column grows far below the right column, and a large empty area appears under the course panel. On desktop, both columns should have the same fixed height, and the competency tree should scroll inside the left column instead of making the page taller.

3. The course panel shrinks when the results contain fewer courses, for example after searching "EDL", and the content below it moves up the page. On desktop, the course panel should keep a fixed height, so the page layout doesn't jump when results change. That height should fit 10 courses, which is one full page of results, even when fewer courses are returned.

4. The mouse cursor doesn't show that a competency row is clickable. Clicking a row selects the competency, but over the row label the cursor is a text cursor instead of a pointer. Every selectable competency row should show a pointer cursor over its whole area.

On small screens, where the two columns stack vertically, the current layout works as intended. Points 1 to 3 apply to the desktop layout only.