fix: unnecessary user selection in recruitment

[shimeoki]

Problem: you can select gaps between buttons in recruitment calculator.

Fix: add user-select: none; to row div's.

I can do a pull request with this fix if you have interest.

Also, as I looked up, these rows don't have a separate class for them. Something like this would probably be better:

.ak-btn-row {
    padding: 0 4px;
    user-select: none;
}