[BUG] Change installation method from npm to native in Docker file

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Docker file users npm installation method for claude code cli which is now deprecated.

What Should Happen?

Update it to use the native installation method

Error Messages/Logs

Steps to Reproduce

NA

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.15

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_