Fix GitHub CLI git authentication setup

Add gh auth setup-git to devcontainer setup script to ensure
git operations use GitHub CLI credentials, preventing auth conflicts.

Author: loujaybee

.devcontainer/setup.sh

@@ -73,6 +73,8 @@ echo "✅ Setup completed successfully!"
 
 if [ -n "$GH_CLI_TOKEN" ]; then
     gh auth login --with-token <<< "$GH_CLI_TOKEN"
+# Configure git to use GitHub CLI credentials
+gh auth setup-git
 else
     echo "GH_CLI_TOKEN not set, skipping authentication"
-fi
+fi