box-drawing characters when npm version installed

[jasonthorsness]

Describe the bug

line-drawing characters for prompt border ──── sometimes are instead box-drawing characters ▄▄▄▄ which strains my eyes.

I found when I use the npm version I see the problem but when I use the native version installed with curl -fsSL https://gh.io/copilot-install | bash I do not see the problem.

The copilot version does not matter, I reproduced it on npm version of 1.0.27 to 1.0.30, it's related to whether it's installed/running via npm or not.

copilot analyzed itself and thinks this:

Root cause: npm install -g @github/copilot installs the JS wrapper but not the optional @github/copilot-linux-x64 native binary package. The npm-loader.js entry point tries to import.meta.resolve() the native binary, fails silently, and falls back to index.js — a Node.js/ink TUI that renders borders with ▄ (half-block characters).

Affected version

1.0.27, 1.0.28, 1.0.29, 1.0.30, maybe earlier too

Steps to reproduce the behavior

npm install -g @github/copilot

start copilot to where you can type a prompt and observe the prompt borders are ▄▄▄

install the curl -fsSL https://gh.io/copilot-install | bash version (even if npm one is already installed) and restart copilot, prompt borders are now ───

My TERM is xterm-256color, this is stock Ubuntu WSL linux

Expected behavior

It should never use ▄▄ no matter how it is installed.

Additional context

No response