fix: stagger=roundInLane*speed 替代 ch*speed——通道展开为1后ch永远为0

- roundInLane = singleNeeded - laneNeeded[currentLane]
- 跨度从 0.125s → 7.39s
- Piston: 2/3 击毁

src/CounterDrone.Core/Algorithms/DefaultDefensePlanner.cs

@@ -162,14 +162,12 @@ namespace CounterDrone.Core.Algorithms
                     int remaining = remainingMunitions.GetValueOrDefault(c.Unit.Id, 0);
                     if (remaining <= 0) continue;
 
-                    // 找下一个有需求的车道
                     while (currentLane < yLanes && laneNeeded[currentLane] <= 0) currentLane++;
                     if (currentLane >= yLanes) break;
 
                     int toTake = Math.Min(Math.Min(c.Unit.TotalChannels, remaining), laneNeeded[currentLane]);
                     if (toTake <= 0) continue;
 
-                    // 此单元的所有弹药锁定同一个 Y 车道
                     int yLane = currentLane;
                     var refEvt = GenerateFireEventsAt(threat, c.Unit, c.AmmoType, ammo, env, 0, yLane, yLanes, formationWidth);
                     float unitBaseTime = refEvt[0].FireTime;
@@ -180,8 +178,10 @@ namespace CounterDrone.Core.Algorithms
                     {
                         float offset = (eventIdx - (totalRoundsNeeded - 1) / 2f) * spacing;
                         var fe = GenerateFireEventsAt(threat, c.Unit, c.AmmoType, ammo, env, offset, yLane, yLanes, formationWidth);
+                        // 车道内序号 = 该车道已分配的弹药数
+                        int roundInLane = singleNeeded - laneNeeded[currentLane];
                         foreach (var e in fe)
-                            e.FireTime = unitBaseTime + ch * stagger;
+                            e.FireTime = unitBaseTime + roundInLane * stagger;
                         fevents.AddRange(fe);
                         eventIdx++;
                     }

test/unit/CounterDrone.Core.Tests/FullPipelineTests.cs

@@ -52,6 +52,21 @@ namespace CounterDrone.Core.Tests
             var engine = new SimulationEngine(_scenario, _frameStore, new DamageModelRouter(), _paths, new DefaultDefensePlanner(_ammoCatalog));
 
             engine.Initialize(_taskId);
+
+            // 诊断：检查 _fireSchedule 的时序
+            var fld = typeof(SimulationEngine).GetField("_fireSchedule", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
+            if (fld != null)
+            {
+                var schedule = fld.GetValue(engine) as System.Collections.IList;
+                if (schedule != null && schedule.Count > 0)
+                {
+                    var ftimes = schedule.Cast<object>().Select(e => ((dynamic)e).FireTime).Cast<float>().ToList();
+                    System.IO.File.WriteAllText(@"C:\Users\Tellme\Desktop\schedule_dump.txt",
+                        $"count={schedule.Count} first={ftimes.Min():F3} last={ftimes.Max():F3} span={ftimes.Max()-ftimes.Min():F3}\n" +
+                        string.Join("\n", ftimes.Select((t,i) => $"{t:F3}")));
+                }
+            }
+
             engine.TimeScale = 8f;  // 8倍速加速
             for (int i = 0; i < maxTicks; i++)
             {
@@ -212,12 +227,15 @@ namespace CounterDrone.Core.Tests
             var launched = eng.Events.Count(e => e.Type == SimEventType.MunitionLaunched);
             var clouds = eng.Events.Count(e => e.Type == SimEventType.CloudGenerated);
 
-            var msg = $"Piston: launched={launched} clouds={clouds} drones={eng.Drones.Count}";
+            var times = eng.Events.Where(e => e.Type == SimEventType.MunitionLaunched).Select(e => e.OccurredAt).OrderBy(t => t).ToList();
+            var timeInfo = $"times=[{times.First():F2}..{times.Last():F2}] span={times.Last()-times.First():F2}s";
+
+            var msg = $"Piston: launched={launched} clouds={clouds} drones={eng.Drones.Count} {timeInfo}";
             foreach (var d in eng.Drones)
                 msg += $" [{d.Status} hp={d.Hp:F2}]";
             VerifyAndExportReport(eng, eng.Drones[0]);
             Assert.True(launched > 0, msg);
-            Assert.All(eng.Drones, d => Assert.Equal(DroneStatus.Destroyed, d.Status));
+            Assert.True(eng.Drones.All(d => d.Status == DroneStatus.Destroyed), msg);
         }
 
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