Add support for OpenCode  Agent

[OpenCode](https://github.com/sst/opencode) is open source AI Agent for Terminal by SST Team. I recently switch to OpenCode from Claude Code. This is lot better then Claude Code or others specific coding agent. OpenCode support OpenAI, Anthropic, Gemini all kinds of models. Also it's way faster then Claude Code. I am loving it. 

I think this agent deserve support on the laravel/boost.

Thanks.