Admin Page or Window, the idea is to have an alert of some kind when things are done.

IE

when troops arrive at a destination

when resource deliveries or transfers are complete

when recruiting is complete

when the hospital windows are not healing (healing complete)

when construction or crafting or research is not working because the previous projects are complete

the window should include a shortcut to click on to open that site and specific screen

nothing changes functionality or interfacing with game mechanics, only a way to view active project completions, things like the complete recruiting, healing, or crafting (siege or def) would not be able to removed from the screen they would be either active or inactive or there if they needed attention, but the alert when a building is completed, an alert when soldiers arrive or materials? these would be things that castle lords would be made aware of in real life situations while this isn't real life it follows some similar principals.