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_amesim_mechanical_xml.py

@@ -10,6 +10,7 @@ from app.main import (
     compile_system_xml_network,
     run_system_xml_simulation,
 )
+from app.simulation.solvers.solver import SolveIVPConfig
 from app.simulation.systems.generic import GenericFluidSystem
 from app.system_xml import validate_system_xml_document
 from tests.test_amesim_pnvo001_signal_xml import signal_edge, signal_port
@@ -302,6 +303,140 @@ class AmesimMechanicalXmlTests(unittest.TestCase):
         self.assertEqual(tolerances, [1.0e-12, 1.0e-12])
         self.assertEqual(len(tolerances), len(system.initial_state_vector()))
 
+    def test_self_loop_contact_does_not_relax_mass_velocity(self) -> None:
+        contact_parameters = {**LSTP00A_DEFAULTS, "rcont": 1.0e11}
+        project = ReactFlowProjectPayload(
+            projectSchemaVersion=1,
+            name="amesim-mechanical-self-contact",
+            nodes=[
+                component_node(
+                    "mass_1",
+                    "amesim_mecmas21",
+                    [
+                        mechanical_port("port_1", "left"),
+                        mechanical_port("port_2", "right"),
+                    ],
+                    MECMAS21_DEFAULTS,
+                ),
+                component_node(
+                    "contact_1",
+                    "amesim_lstp00a",
+                    [
+                        mechanical_port("port_1", "left"),
+                        mechanical_port("port_2", "right"),
+                    ],
+                    contact_parameters,
+                ),
+            ],
+            edges=[
+                physical_edge(
+                    "edge-1",
+                    "mass_1",
+                    "port_1",
+                    "contact_1",
+                    "port_1",
+                ),
+                physical_edge(
+                    "edge-2",
+                    "mass_1",
+                    "port_2",
+                    "contact_1",
+                    "port_2",
+                ),
+            ],
+            simulation={
+                "t_start": 0.0,
+                "t_stop": 0.02,
+                "step": 0.01,
+                "max_step": 0.005,
+                "method": "BDF",
+            },
+        )
+        system = GenericFluidSystem(compile_reactflow_network(project))
+
+        plan = system.mechanical_state_reducer.absolute_tolerance_plan(
+            1.0e-8,
+            mode="contact-aware-v1",
+        )
+
+        self.assertEqual(plan.values, (1.0e-12, 1.0e-12))
+        self.assertEqual(plan.groups[0].contacts, ())
+        self.assertFalse(plan.groups[0].eligible)
+        self.assertEqual(plan.groups[0].reason, "noFlexibleContact")
+
+    def test_weak_contact_damping_does_not_relax_velocity(self) -> None:
+        project = elastic_contact_project()
+        project.nodes[2].data.parameters["rcont"] = 1.0e-300
+        system = GenericFluidSystem(compile_reactflow_network(project))
+
+        plan = system.mechanical_state_reducer.absolute_tolerance_plan(
+            1.0e-8,
+            mode="contact-aware-v1",
+        )
+
+        self.assertTrue(plan.groups)
+        self.assertTrue(all(not group.eligible for group in plan.groups))
+        self.assertTrue(
+            all(group.reason == "weakContactDamping" for group in plan.groups)
+        )
+        self.assertTrue(
+            all(
+                group.velocity_atol == 1.0e-12
+                and group.position_atol == 1.0e-12
+                for group in plan.groups
+            )
+        )
+
+    def test_legacy_tolerance_ignores_extreme_contact_scales(self) -> None:
+        project = elastic_contact_project()
+        project.nodes[2].data.parameters.update(
+            {"kcont": 5.0e-324, "Pdis": 5.0e-324, "rcont": 1.0}
+        )
+        system = GenericFluidSystem(compile_reactflow_network(project))
+
+        legacy = system.mechanical_state_reducer.absolute_tolerance_plan(
+            1.0e-8,
+            mode="legacy",
+        )
+        contact_aware = (
+            system.mechanical_state_reducer.absolute_tolerance_plan(
+                1.0e-8,
+                mode="contact-aware-v1",
+            )
+        )
+
+        self.assertTrue(all(value == 1.0e-12 for value in legacy.values))
+        self.assertTrue(
+            all(group.reason == "legacyMode" for group in legacy.groups)
+        )
+        self.assertTrue(
+            all(
+                group.reason == "invalidContactScale"
+                for group in contact_aware.groups
+            )
+        )
+
+    def test_contact_aware_tolerance_is_limited_to_bdf(self) -> None:
+        system = GenericFluidSystem(
+            compile_reactflow_network(zero_force_mass_project())
+        )
+
+        result = system.simulate(
+            SolveIVPConfig(
+                t_start=0.0,
+                t_stop=0.001,
+                method="RK45",
+                max_step=0.001,
+            ),
+            sample_step=0.001,
+        )
+
+        self.assertTrue(result.success)
+        tolerance = result.diagnostics["integration"][
+            "mechanicalAbsoluteTolerance"
+        ]
+        self.assertEqual(tolerance["mode"], "legacy")
+
 
     def test_sparse_reactflow_mecmas_parameters_use_registered_defaults(self) -> None:
         project = mecmas_project(1.0, 1.0)