整合求解器活动监控与步长回归证据

同步远端 PNL0003 诊断和大采样网格能力，语义合并活动感知的 60 秒真停滞判定与旧后端 15 分钟兼容兜底。

纳管热路径优化、15 单元运行证据、浏览器与 API 报告，并补充北京时间更新日志和遗留问题。

tests/test_max_step_matrix.py

@@ -166,7 +166,7 @@ class MaxStepMatrixTests(unittest.TestCase):
             DEFAULT_MANIFEST_PATH,
             horizon_case_ids=("1s", 2.0),
             max_steps=(0.01, 0.05),
-            additional_checkpoint_times=(1.0885267285, 1.0997760276),
+            additional_checkpoint_times=(1.08, 1.10),
             expected_projection_count=2,
             case_executor=execute,
         )
@@ -180,7 +180,7 @@ class MaxStepMatrixTests(unittest.TestCase):
         custom_requests = [request for request in requests if request.stop_time == 2.0]
         self.assertEqual(
             custom_requests[0].checkpoint_times,
-            (0.0, 0.04, 0.8, 1.0, 1.0885267285, 1.0997760276, 2.0),
+            (0.0, 0.04, 0.8, 1.0, 1.08, 1.1, 2.0),
         )
         self.assertEqual(
             report["configuration"]["horizons"][1]["horizonCaseId"],
@@ -248,6 +248,50 @@ class MaxStepMatrixTests(unittest.TestCase):
             prefix_comparisons[0]["stateProjection"]["valueMismatchCount"], 0
         )
 
+    def test_cross_horizon_comparison_excludes_short_terminal(self) -> None:
+        def execute(request: RegressionCaseRequest) -> dict[str, object]:
+            result = _fake_completed(request)
+            if request.stop_time <= 1.0:
+                checkpoints = result["worker"]["summary"]["physicalContract"][
+                    "checkpoints"
+                ]
+                for checkpoint in checkpoints:
+                    if checkpoint["requestedTime"] == request.stop_time:
+                        checkpoint["stateValues"]["state.a"] += 1.0
+            return result
+
+        report = run_max_step_matrix(
+            DEFAULT_MANIFEST_PATH,
+            horizon_case_ids=("1s", 2.0),
+            max_steps=(0.01,),
+            expected_projection_count=2,
+            case_executor=execute,
+        )
+
+        comparison = report["comparisons"]["sameMaxStepAcrossHorizons"][0]
+        self.assertTrue(comparison["strictPrefix"])
+        self.assertTrue(comparison["passed"])
+        self.assertNotIn(
+            1.0,
+            comparison["stateProjection"]["commonCheckpointTimes"],
+        )
+
+    def test_same_horizon_comparison_keeps_terminal_checkpoint(self) -> None:
+        report = run_max_step_matrix(
+            DEFAULT_MANIFEST_PATH,
+            horizon_case_ids=("1s",),
+            max_steps=(0.01, 0.05),
+            expected_projection_count=2,
+            case_executor=_fake_completed,
+        )
+
+        comparison = report["comparisons"]["sameHorizonAcrossMaxSteps"][0]
+        self.assertFalse(comparison["strictPrefix"])
+        self.assertIn(
+            1.0,
+            comparison["stateProjection"]["commonCheckpointTimes"],
+        )
+
     def test_horizons_must_increase_and_timeout_override_is_bounded(self) -> None:
         with self.assertRaisesRegex(
             RegressionManifestError, "strictly increasing"
@@ -259,6 +303,20 @@ class MaxStepMatrixTests(unittest.TestCase):
                 expected_projection_count=2,
                 case_executor=_fake_completed,
             )
+
+    def test_off_grid_checkpoint_is_rejected_before_execution(self) -> None:
+        with self.assertRaisesRegex(
+            RegressionManifestError,
+            "not represented by the .* output grid",
+        ):
+            run_max_step_matrix(
+                DEFAULT_MANIFEST_PATH,
+                horizon_case_ids=("1s",),
+                max_steps=(0.01,),
+                additional_checkpoint_times=(0.0489,),
+                expected_projection_count=2,
+                case_executor=_fake_completed,
+            )
         with self.assertRaisesRegex(RegressionManifestError, "must exceed"):
             run_max_step_matrix(
                 DEFAULT_MANIFEST_PATH,