`gh auth login` has `tls: failed to verify certificate: x509: certificate signed by unknown authority`

This issue is to track the termux-docker variant of tls: failed to verify certificate: x509: certificate signed by unknown authority.

Every type of termux-docker has this issue, and my recent heavy changes did not introduce it. Unfortunately, I didn't fix it because I don't know how to.

Sometimes, GNU/Linux or normal Android can have tls: failed to verify certificate: x509: certificate signed by unknown authority also, but when they do, it's thought to be due to a different root cause, because generic solutions for this error from GNU/Linux and normal Android don't seem to help.

Some known affected programs:

GitHub CLI
Git LFS

Most programs are not known to be affected.

Reproduction steps

GitHub CLI

docker run -it termux/termux-docker:x86_64 # any architecture
pkg upgrade
pkg install gh
gh auth login

Git LFS

https://github.com/termux-user-repository/tur/blob/f7e2985791ed5824f3e3600deff4243c2ce3b711/tur-on-device/blender4/build.sh#L48-L57

Only currently known workarounds

GitHub CLI

# add the SSH remote of your repo to your local clone
git remote add ssh git@github.com:you/your-repo.git
# create SSH key inside termux-docker and add it to your GitHub account, then
git push -f ssh your-branch

Git LFS

export GIT_SSL_NO_VERIFY=1

Start by reproducing the failure in the termux/termux-docker image with pkg upgrade, pkg install gh, and gh auth login; also inspect the referenced Git LFS build.sh section. Trace why certificate authorities are unavailable in termux-docker, then verify that GitHub CLI and Git LFS work without SSH-only access or GIT_SSL_NO_VERIFY=1.