Fix _upsert_post to return (post, old_status) tuple

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

bp/blog/ghost/ghost_sync.py

@@ -271,7 +271,7 @@ async def _upsert_post(sess: AsyncSession, gp: Dict[str, Any], author_map: Dict[
             sess.add(PageConfig(container_type="page", container_id=obj.id, features={}))
             await sess.flush()
 
-    return obj
+    return obj, old_status
 
 async def _ghost_find_member_by_email(email: str) -> Optional[dict]:
     """Return first Ghost member with this email, or None."""