refactor: 移除所有非ollama引擎，新增OpenAI兼容格式引擎

- 删除: mimo_engine, GLM_http_engine, qwq_engine, xfyun_spark_engine, iflow_api_engine, maas_http_engine, SDK_openAI
- 保留: ollama_engine (本地Ollama引擎)
- 新增: openai_engine (通用OpenAI API兼容引擎，支持DeepSeek/Grok/硅基流动/vLLM等)
- 新增: config.json.example 配置模板
- 更新: README.md / README.en.md 引擎说明

README.en.md

@@ -14,7 +14,7 @@
 
 ## ✨ Features
 
-- 🤖 **Multi AI Engines** — Ollama, MiMo, GLM, QwQ, MaaS and more
+- 🤖 **Multi AI Engines** — Ollama local models + OpenAI compatible format (DeepSeek, Grok, SiliconFlow, etc.)
 - 🔧 **Precise Code Editing** — Search & replace, batch edits, diff comparison, line-level operations
 - 🔍 **Code Search & Understanding** — Cross-file search, regex matching, symbol extraction, dependency analysis
 - 🔄 **Git Integration** — Full Git workflow support
@@ -43,7 +43,7 @@ python -m xiaoli
 python -m xiaoli --cli
 
 # Specify engine
-python -m xiaoli --engine mimo
+python -m xiaoli --engine openai
 
 # Show version
 python -m xiaoli --version