Allow a `-y` or similar flag with `claude migrate-installer` for non-tty environments.

Question

I want the following in my `Dockerfile` -
```
RUN npm install -g @anthropic-ai/claude-code
RUN claude migrate-installer
RUN claude update
```

but it failes because `migrate-installer` wants me to press Enter before it will proceed and there is no way to do that in Dockerfile.