fix: use --force flag for gh auth setup-git in Docker build

gh auth setup-git requires an authenticated session, which doesn't
exist during docker build. The --force flag with --hostname skips
the auth check and configures the credential helper anyway. At
runtime, GH_TOKEN env var provides the actual credentials.

Verified locally: docker build succeeds, git ls-remote against a
private repo works with GH_TOKEN.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: AbirAbbas

Dockerfile

@@ -33,7 +33,7 @@ ENV GIT_AUTHOR_NAME="SWE-AF" \
 # HTTPS operations (clone, push, fetch) authenticate via GH_TOKEN at runtime.
 RUN git config --global user.name "SWE-AF" && \
     git config --global user.email "contact@agentfield.com" && \
-    gh auth setup-git
+    gh auth setup-git --hostname github.com --force
 
 # Install uv for fast package installation
 RUN pip install --no-cache-dir uv