Show the active env in Claude Code statusline

Surface CVM_ENV so parallel tabs stay identifiable.

Paste a prompt like the following into Claude Code and let it adapt your existing statusLine script:

Please update my Claude Code statusline so it shows the active cvm
environment when there is one. Find my current statusLine configuration
and adjust its command/script in place without removing existing output.

Requirements:
- If CVM_ENV is set and non-empty, prepend a short badge (e.g. [env-name]).
- If CVM_ENV is unset/empty, render exactly as today.
- Keep the existing language/tooling of the statusline script.
- If none exists, create a minimal one with model name + CVM_ENV badge.

Show me the diff before writing it.

CVM_ENV is set for processes started via use, run, and open.