fix(pd): disable overlap for spec+grammar in disagg decode loop (#28039)

test/registered/disaggregation/test_disaggregation_basic.py

@@ -10,6 +10,7 @@ import requests
 from transformers import AutoTokenizer
 
 from sglang.test.ci.ci_register import register_cuda_ci
+from sglang.test.kits.json_constrained_kit import JSONConstrainedMixin
 from sglang.test.kits.pause_generation_kit import PauseResumeInPlaceMixin
 from sglang.test.run_eval import run_eval
 from sglang.test.server_fixtures.disaggregation_fixture import (
@@ -21,7 +22,7 @@ from sglang.test.test_utils import (
     DEFAULT_TARGET_MODEL_EAGLE3,
 )
 
-register_cuda_ci(est_time=509, stage="base-b", runner_config="2-gpu-large")
+register_cuda_ci(est_time=560, stage="base-b", runner_config="2-gpu-large")
 
 
 class TestDisaggregationAccuracy(PauseResumeInPlaceMixin, PDDisaggregationServerBase):
@@ -215,7 +216,7 @@ class TestDisaggregationMooncakeFailure(PDDisaggregationServerBase):
                 raise e from health_check_error
 
 
-class TestDisaggregationMooncakeSpec(PDDisaggregationServerBase):
+class TestDisaggregationMooncakeSpec(JSONConstrainedMixin, PDDisaggregationServerBase):
     @classmethod
     def setUpClass(cls):
         super().setUpClass()