fetch/rebase is blocked by network policy in Codex Web

What issue are you seeing?

Codex Web is wicked cool (thank you), but, small issue: upstream sync is blocked at network.

What steps can reproduce the bug?

git remote add upstream https://github.com/<org>/<repo>.git
git fetch upstream master
fatal: unable to access 'https://github.com/<org>/<repo>.git/': CONNECT tunnel failed, response 403

What is the expected behavior?

This is not a git workflow error; fetch is blocked by network/proxy policy.
Please expose/enable a supported upstream sync path for pre-mounted repos, or provide an alternative for rebasing onto upstream.

Additional information

Not a security issue.