How to use plan mode with claude-code-action?

## Context
I'm building an automated AI agent called **Kanbino** that uses the `claude-code-action` to implement tasks
automatically via GitHub Actions. I want to support a two-step workflow:

1. **Plan mode**: Claude analyzes the task and generates an implementation plan
2. **Execute mode**: Claude implements the approved plan

I couldn't find this in the docs, so I wanted to ask: does the action support a native plan mode similar to the CLI's
--plan flag? If not, what's the recommended approach to get Claude to generate a plan without making any code changes?