Add "Last Logged In" Information and User Login Statistics

[GeekStreetSolutions]

It would be very useful to expand the Users page with additional information about user activity.

Requested Features

• Add a Last Logged In column showing the date and time each user most recently logged into Seerr.
• Add a Total Logged-In Users counter showing how many user accounts are actively logged in.
• (Optional) Allow sorting the user list by Last Logged In so inactive accounts can be identified quickly.

Benefits

• Makes it easy to identify users who have never signed in after being invited.
• Helps administrators determine which accounts are active versus inactive.
• Makes it easier to clean up old or unused user accounts.
• Helps administrators verify that new users have successfully accessed the service.
• Provides a quick overview of actual Seerr usage without having to inspect each account individually.

This would be a simple quality-of-life improvement for administrators managing servers with family members, friends, or larger user bases.