fix: Mag2 环线补锁失败时不再派车

TrafficReset 失败则跳过 AssignCarToTarget，避免无锁占用仍打上 goalSite。

Co-authored-by: Cursor <cursoragent@cursor.com>

StandardScene.Magnetic/Chained/Mag2LoopMission.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using Newtonsoft.Json;
+using LessokajiWeaverUtilities.Utilities;
 using SimpleCore;
 using SimpleCore.Library;
 using Simple3;
@@ -64,9 +65,9 @@ namespace StandardScene
         /// </summary>
         protected override void AssignCarToTarget(Car car, int targetSiteId)
         {
-            if (car is Mag2Car mag2)
+            if (car is Mag2Car mag2 && !EnsureMag2HoldingCurrentSite(mag2))
             {
-                EnsureMag2HoldingCurrentSite(mag2);
+                return;
             }
 
             base.AssignCarToTarget(car, targetSiteId);
@@ -183,26 +184,31 @@ namespace StandardScene
             };
         }
 
-        private static void EnsureMag2HoldingCurrentSite(Mag2Car car)
+        private static bool EnsureMag2HoldingCurrentSite(Mag2Car car)
         {
             try
             {
                 if (car.status?.holdingLocks != null && car.status.holdingLocks.Length == 1)
-                    return;
+                    return true;
 
                 var siteId = car.siteID > 0 ? car.siteID : car.GetLastSite();
                 if (siteId <= 0)
-                    return;
+                    return false;
 
                 var site = SimpleLib.GetSite(siteId);
                 if (site == null)
-                    return;
+                    return false;
 
                 car.TrafficReset(site, true, strict: false);
+                return true;
             }
-            catch (Exception)
+            catch (Exception ex)
             {
-                // 交管失败时仍允许打上 goalSite，后续 GoSite/状态机会再处理
+                Diagnosis.Post(
+                    $"Mag2 补交管锁失败，跳过派车 car={car?.id}：{ex.Message}",
+                    "Mag2Loop",
+                    true);
+                return false;
             }
         }
     }