Fix harness SLO early-stop diagnosis

src/aituner/harness.py

@@ -607,6 +607,7 @@ def _active_bottleneck(probe: dict[str, Any] | None) -> str:
         if not str(k).startswith("ttft")
         and not str(k).startswith("tpot")
         and not str(k).startswith("probe_elapsed_s>")
+        and str(k) != "slo_pass_rate_unrecoverable"
     )
     if ttft_count == 0 and tpot_count == 0 and request_failed_count == 0:
         return "none_obvious"