📁 重组文档目录结构

变更：
- 创建 docs/ 目录统一管理所有文档
- 移动所有 API 文档到 docs/ 目录
  - API_DOCS_INDEX.md
  - RESTFUL_API_DOCUMENTATION.md
  - API_SERVICE_README.md
  - API_CLIENT_EXAMPLES.md
  - API_SERVICE_GUIDE.md
  - BRANCH_README.md
  - openapi.yaml
  - IOPaint_API.postman_collection.json
  - UPGRADE_NOTES.md

- 更新所有文档间的引用路径
- 更新 README.md 中的文档链接
- 创建 docs/README.md 作为文档入口

优势：
✅ 清晰的目录结构
✅ 文档集中管理
✅ 易于查找和维护
✅ 符合项目规范

🔧 Generated with Claude Code

docs/README.md

@@ -0,0 +1,77 @@
+# IOPaint API Service Documentation
+
+Welcome to the IOPaint API Service documentation! This directory contains all the documentation for the API service branch.
+
+## 📑 Documentation Index
+
+### Quick Start
+- **[API Service README](./API_SERVICE_README.md)** - 🚀 Get started in 10 minutes
+- **[Documentation Index](./API_DOCS_INDEX.md)** - 📑 Complete navigation guide
+
+### API Reference
+- **[RESTful API Documentation](./RESTFUL_API_DOCUMENTATION.md)** - 📖 Complete API reference (OpenAI style)
+- **[OpenAPI Specification](./openapi.yaml)** - 🔧 OpenAPI 3.0.3 spec file
+- **[Postman Collection](./IOPaint_API.postman_collection.json)** - 🧪 API testing collection
+
+### Integration & Examples
+- **[Client Examples](./API_CLIENT_EXAMPLES.md)** - 💻 Multi-language code examples
+  - Python (Basic + Advanced)
+  - JavaScript/Node.js
+  - PHP
+  - Go
+  - Java
+  - cURL/Bash
+
+### Deployment & Architecture
+- **[Service Guide](./API_SERVICE_GUIDE.md)** - 🏗️ MVP to production deployment guide
+  - Architecture design (Docker → Kubernetes)
+  - Cost analysis & revenue models
+  - Implementation roadmap
+
+### Branch Information
+- **[Branch README](./BRANCH_README.md)** - 🌿 Branch comparison and switching guide
+- **[Upgrade Notes](./UPGRADE_NOTES.md)** - 📝 Package upgrade history
+
+## 🎯 Choose Your Path
+
+### I want to...
+
+**...get started quickly**
+→ Read [API_SERVICE_README.md](./API_SERVICE_README.md)
+
+**...integrate the API**
+→ Read [RESTFUL_API_DOCUMENTATION.md](./RESTFUL_API_DOCUMENTATION.md) + [API_CLIENT_EXAMPLES.md](./API_CLIENT_EXAMPLES.md)
+
+**...test the API**
+→ Import [IOPaint_API.postman_collection.json](./IOPaint_API.postman_collection.json) or visit http://localhost:8080/docs
+
+**...deploy for production**
+→ Read [API_SERVICE_GUIDE.md](./API_SERVICE_GUIDE.md)
+
+**...understand branch differences**
+→ Read [BRANCH_README.md](./BRANCH_README.md)
+
+## 📊 Documentation Stats
+
+| Type | Files | Pages | Languages |
+|------|-------|-------|-----------|
+| Core Docs | 6 | ~120 | - |
+| Code Examples | 1 | ~28 | 6 |
+| Spec Files | 2 | - | - |
+| **Total** | **9** | **~150** | **6** |
+
+## 🔗 External Links
+
+- **Repository**: https://github.com/let5sne/IOPaint
+- **API Branch**: https://github.com/let5sne/IOPaint/tree/feature/api-service
+- **Main Branch**: https://github.com/let5sne/IOPaint/tree/main
+
+## 📞 Support
+
+- **GitHub Issues**: https://github.com/let5sne/IOPaint/issues
+- **Documentation Feedback**: Open an issue with label `documentation`
+
+---
+
+**Last Updated**: 2025-11-28
+**Version**: 1.0.0