fix: use -R flag on gh commands to bypass remote resolution

The gh CLI fails with 'none of the git remotes correspond to GH_HOST'
because it tries to resolve the repo from git remotes when GH_HOST is
set to the proxy. Using -R $GITHUB_REPOSITORY explicitly specifies the
repo, bypassing remote resolution entirely.

Also adds git remote -v debug output to verify proxy remote is added.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: lpcox