tea pr create matches the remote URL against the configured login URL to
auto-detect owner/repo. Embedding credentials in the URL (user:token@host)
breaks that match and produces "path segment [0] is empty". Store creds
via git credential helper instead and pass a clean URL to uh-cli.
Also adds set -x to the PR step for shell-level tracing in CI logs.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
