agentic git commit generate tool

• https://github.com/Nutlope/aicommits
• https://chat.deepseek.com

• OPENAI_API_KEY
• OPENAI_BASE_URL, default: https://api.deepseek.com/v1
• OPENAI_MODEL, default: deepseek-chat