When is a War Over?

Over the course of the current war, I've often come across "objections" of the sort expressed here:

if the AUMF is equivalent to a declaration of war, then how will we know when we are no longer at war? Previous declarations of war have typically ended in a peace treaty of some sort. I don't see that happening in this case. I imagine at some point in the future the US will pull its combat troops out of Iraq. However, I don't expect a formal peace treaty to be signed at that time.

I shouldn't need to point out that "typically" is not exactly a term of constitutional significance. What happens typically has nothing to do with what is required.

But let's set that aside. OK, a war is over when a formal peace treaty is signed. Now tell me, o Wise One, when WW2 ended. Do you see a problem with that? Does it make WW2 somehow less legitimate?

For that matter, wars sometimes do go on for many years or decades. Heard of the Hundred Years War? Is there some guarantee in the constitution that wars the USA enters into may not last more than a certain number of years? I've never come across one.