Prevent client-side clipping in vLLM grid

runs/frontier-multicase-sufficiency-v0/best_effort/test_community_prefill_grid.py

@@ -40,6 +40,8 @@ def test_study_uses_raw_prompt_and_fixed_serving_contract(tmp_path: Path) -> Non
     assert payload["trace"]["request_mode"] == "raw_completion"
     assert payload["trace"]["completion_tokens_override"] == 1
     assert payload["trace"]["replay_time_scale"] == 1.0
+    assert payload["trace"]["max_concurrency"] == 256
+    assert payload["trace"]["max_concurrency"] > max(item.mns for item in MODULE.GRID)
     assert payload["engine"]["base_flags"]["enable-expert-parallel"] is True
     assert payload["engine"]["base_flags"]["disable-custom-all-reduce"] is True
     assert payload["engine"]["base_flags"]["num-gpu-blocks-override"] == 62351