docs: complete coordinator client docstring

scripts/ci/organization_commercial_readiness_loop.py

@@ -239,6 +239,7 @@ class GitHubClient:
     """Use the GitHub CLI as an authenticated, bounded REST transport."""
 
     def __init__(self, token: str, *, timeout_seconds: int = 60) -> None:
+        """Initialize the client with one bounded GitHub credential."""
         if not token:
             raise GitHubError("GH_TOKEN is required for organization coordination")
         self._token = token
@@ -853,4 +854,4 @@ def main(
 
 
 if __name__ == "__main__":  # pragma: no cover - exercised through main()
-    raise SystemExit(main())
+    raise SystemExit(main())