fix: clarify stale release token recovery (#37)

src/release_engine.py

@@ -147,6 +147,8 @@ class GiteaClient:
                 return json.loads(raw) if raw else None
         except error.HTTPError as exc:
             detail = exc.read().decode(errors="replace")
+            if exc.code == 401:
+                detail += " (authentication rejected; refresh the cron GITEA_TOKEN)"
             raise RuntimeError(f"Gitea {method} {path} failed: HTTP {exc.code}: {detail}") from exc
 
     @staticmethod