initial: project structure and documentation setup

- Create project directory structure
- Initialize Go module
- Set up development documentation (why.md, taolun.md, changelog.md, memory.md, AGENTS.md)
- Configure YAML config template
- Set up .gitignore and .env.example
- Design OOP architecture with factory and strategy patterns

Version: 0.0.1

.env.example

@@ -0,0 +1,13 @@
+# YOYO翻译工具环境变量配置
+# 复制此文件为.env并填入您的API密钥
+
+# 大模型API配置
+SILICONFLOW_API_KEY=your_siliconflow_api_key
+VOLCANO_API_KEY=your_volcano_api_key
+NATIONAL_API_KEY=your_national_api_key
+QWEN_API_KEY=your_qwen_api_key
+OPENAI_API_KEY=your_openai_api_key
+
+# 应用配置（可选）
+YOYO_DEFAULT_PROVIDER=siliconflow
+YOYO_TIMEOUT=30