fix: align mechanical dynamic port validation

tests/test_amesim_mechanical_xml.py

@@ -427,6 +427,30 @@ class AmesimMechanicalXmlTests(unittest.TestCase):
         self.assertNotIn("node_1.port_21.f", result["series"])
         self.assertAlmostEqual(result["series"]["mass_1.a"][0], 5.0)
 
+    def test_force_node_rejects_connection_to_inactive_reserved_port(self) -> None:
+        project = force_node_mass_project(2)
+        edge = next(
+            edge
+            for edge in project.edges
+            if edge.id == "edge-mass"
+        )
+        edge.sourceHandle = "port_9"
+
+        with self.assertRaisesRegex(ValueError, "missing endpoint node_1.port_9"):
+            build_reactflow_system_xml(project)
+        with self.assertRaisesRegex(ValueError, "port_9 is not active"):
+            compile_reactflow_network(project)
+
+        xml = build_reactflow_system_xml(force_node_mass_project(2))
+        root = ET.fromstring(xml)
+        endpoint = root.find("./Connections/Connection[@id='edge-mass']/Endpoint[@component='node_1']")
+        assert endpoint is not None
+        endpoint.set("port", "port_9")
+        report = validate_system_xml_document(ET.tostring(root, encoding="utf-8"))
+
+        self.assertFalse(report.valid)
+        self.assertIn("ENDPOINT_PORT_INACTIVE", {issue.code for issue in report.issues})
+
     def test_elastic_contact_project_compiles_and_simulates(self) -> None:
         xml = build_reactflow_system_xml(elastic_contact_project())
         report = validate_system_xml_document(xml)