Current behavior:

Nowadays, it is only possible to configure Pull Requests to be automatically declined after a given number of weeks (1, 2, 4, 8, or 12) have passed:

Automatically decline inactive pull requests

Suggested behavior:

Allow configuring Pull Requests to be automatically declined after a specified number of days have passed, in addition to the current behavior.

The current dropdown (which shows "X weeks") should be changed to show only numbers, and a new dropdown that lets users select between days and weeks should be added next to it.