You are given a sorted array of integers, nums, where all integers appear twice except for one. Your task is to find and return the single integer that appears only once.

本项目是《Agentic Design Patterns》一书的中文翻译项目。该书系统介绍了 AI Agent 系统的各种设计模式，涵盖从基础到高级的 21 个核心模式，以及多个附录章节。