“I have a question,” says Zora (Bella Ramsey) at the first-act turning point in Kyle Balda’s “The Sheep Detectives.” “The Sheep Detectives” is a cozy murder mystery, so it’s not surprising that characters have questions. Zora, though, is a curious youngster learning for the first time about human mortality, and her questions go beyond typical whodunit riddles: “What is the meaning of human life, if it can all just end in the blink of an eye? In fact, why are humans here at all?