Thanks everyone for your advice!
Actually, you bring up a good point,
@reddesert. One strange thing I noticed when I first picked up the camera was that when it's set to long focal lengths, the focusing ring moves when I pull the advance lever! I'm guessing that this is not normal behavior (though someone who knows these cameras better than me should correct me if I'm wrong). Here are two images that show what happens with the focusing ring when the film advance/shutter cocking lever is pulled:
Also, the front of the lens assembly is ever so slightly loose with respect to the focusing ring and the front plate of the camera. If I turn the front of the lens and maintain pressure on it, I can almost reliably get the shutter to cock when the advance lever is pulled. (So I'm guessing someone badly reassembled the camera in the past?) I had been hoping to avoid taking apart the lens assembly more than I already have, but I don't really have anything to lose at this point... I suppose I'll try your suggestions first,
@OAPOli, since they're easier, and if that doesn't work, I'll go down deeper into the lens.
Worst comes to worst, I've wasted some time on a funny project taking apart a camera. Best case scenario, I'll have a working camera for 20€!