After being derailed in every direction by flowers that need picking, cave bears that need stomping and nobles who need their house emptied of anything remotely valuable, I'm finally going to continue the main quests. So I'm just wondering, if I hold off on the civil war to see the peace treaty, will the effects of this treaty be permanent and end the war? Or is it just an "until Alduin gets whacked" sort of treaty, which lets me unleash mayhem and destruction upon Skyrim again once I've cleaned up the reptilian mess?

The very nature behind a "truce" means it's never permanent. A "permanent" truce is more akin to a Treaty or hell, the end of a war, making the term moot.

So, uh. Yea.

cessation of hostilities until the dragon issue is handled.

Aye, just wanted to make sure the duration of the truce wouldn't go beyond the game's timeline so to speak.

The peace itself doesn't last. Like the war does continue afterward. However the concessions each side made during the negotiations are permanent. At the peace negotiations, each side has to give ground to the other, and it's up to you to decide the outcome.