Back-office roles & dual roles as administrator and driver

The back-office management role is now separate from the driver role. A single user can be an Admin or Dispatcher while also serving as an active driver in the fleet, without needing a second account. When inviting a team member, you can choose their access level (Admin, Dispatcher, Member) and specify whether they will be making trips, along with their commission rate. The member table has been redesigned for greater clarity.