修复云团间距半径基准不一致 + 消除硬编码 30f

逻辑层修复（前端反馈的云团缝隙问题）：
- ComputeEffectiveRadius 应用 ExpansionFactor，返回穿越时刻半径
- 间距/车道/弹药数统一用 effectiveRadius（原用 turbulentRadius=R30）
- TryGenerateFireEvents 复用 ComputeEffectiveRadius，消除重复计算
- 概率计算间距也加重叠系数
- GaussianPuffDispersion 消除硬编码 30f，读 _ammo.Phase2Duration
- DefensePlanner 消除硬编码 30f，读 model.Phase2Duration
- 265 测试通过，Unity 编译通过

src/CounterDrone.Core/Algorithms/DefensePlanner.cs

@@ -138,16 +138,16 @@ namespace CounterDrone.Core.Algorithms
 
                 // 单机需求
                 var (effectiveRadius, expansionTime, turbulentRadius) = ComputeEffectiveRadius(ammo, env);
-                int singleNeeded = CalcRoundsNeeded(threat, ammo, env, false, turbulentRadius);
+                int singleNeeded = CalcRoundsNeeded(threat, ammo, env, false, effectiveRadius);
 
                 // 车道划分（可替换策略）
-                var (yLanes, laneSpacing) = _laneDivider.Divide(threat, turbulentRadius);
+                var (yLanes, laneSpacing) = _laneDivider.Divide(threat, effectiveRadius);
                 float formationWidth = yLanes > 1 ? (yLanes - 1) * laneSpacing : 0f;
                 int totalRoundsNeeded = singleNeeded * yLanes;
 
                 // 逐单元分配：每个单元锁定一个 Y 车道
-                // 云团间距 = 2R × (1 - 重叠比例)，重叠由配置驱动，保证有效区互相覆盖
-                float spacing = 2f * turbulentRadius * (1f - _config.CloudOverlapRatio);
+                // 云团间距 = 2R × (1 - 重叠比例），R 为穿越时刻的有效半径，保证无缝覆盖
+                float spacing = 2f * effectiveRadius * (1f - _config.CloudOverlapRatio);
                 int[] laneNeeded = new int[yLanes];
                 float[] laneBaseTime = new float[yLanes];
                 bool[] laneBaseSet = new bool[yLanes];
@@ -178,7 +178,7 @@ namespace CounterDrone.Core.Algorithms
                         laneBaseTime[yLane] = refEvt[0].FireTime;
                         laneBaseSet[yLane] = true;
                     }
-                    float stagger = Kinematics.CloudCoverInterval(turbulentRadius * 2f, GetDroneSpeedKph(threat), c.Unit.ChannelInterval);
+                    float stagger = Kinematics.CloudCoverInterval(effectiveRadius * 2f, GetDroneSpeedKph(threat), c.Unit.ChannelInterval);
 
                     var fevents = new List<FireEvent>();
                     int unitIdx = fireUnits.IndexOf(c.Unit);
@@ -381,10 +381,8 @@ namespace CounterDrone.Core.Algorithms
             AmmunitionSpec ammo, CombatScene env)
         {
             var model = new CloudExpansionModel(ammo, env);
-            float rPhase2 = model.RadiusAt(30f);
-            float expansionTime = model.TimeToReach(rPhase2);
-            // 云团被穿过时的真实年龄 = expansionTime（云团生成后膨胀到有效半径的时长）。
-            // 这是云团自身的物理量，与无人机飞行时间无关。
+            float rPhase2 = model.RadiusAt(model.Phase2Duration);
+            float expansionTime = model.TimeToReach(rPhase2) * _config.ExpansionFactor;
             float effectiveR = model.RadiusAt(expansionTime);
             return (effectiveR, expansionTime, rPhase2);
         }
@@ -407,7 +405,7 @@ namespace CounterDrone.Core.Algorithms
         {
             float avgSpeed = GetDroneSpeedMs(threat);
             var (effectiveR, _, _) = ComputeEffectiveRadius(ammo, env);
-            float spacing = 2f * effectiveR;
+            float spacing = 2f * effectiveR * (1f - _config.CloudOverlapRatio);
             float actualCoverage = spacing * (rounds - 1) + 2f * effectiveR;
             float actualExposure = actualCoverage / avgSpeed;
 
@@ -430,10 +428,7 @@ namespace CounterDrone.Core.Algorithms
             if (wps == null || wps.Count < 2) return (events, "航路无效");
 
             var cloudModel = new CloudExpansionModel(ammo, env);
-            // 云龄 = expansionTime（云团生成后膨胀到有效半径的时长）
-            float effectiveAge = cloudModel.TimeToReach(cloudModel.TurbulentRadius) * _config.ExpansionFactor;
-            float effectiveR = cloudModel.RadiusAt(effectiveAge);
-            float expansionTime = cloudModel.TimeToReach(effectiveR);
+            var (effectiveR, expansionTime, _) = ComputeEffectiveRadius(ammo, env);
 
             float densityAtPassage = cloudModel.DensityAt(expansionTime);
             if (densityAtPassage < (float)ammo.EffectiveConcentration)

src/CounterDrone.Core/Algorithms/GaussianPuffDispersion.cs

@@ -61,7 +61,7 @@ namespace CounterDrone.Core.Algorithms
             var (vx, vy, vz) = Kinematics.WindToVector(windDir, windSpeed);
             _windVelocity = new Vector3(vx, vy, vz);
 
-            if (!_inPhase3 && _elapsed >= 30f)
+            if (!_inPhase3 && _elapsed >= (float)_ammo.Phase2Duration)
                 _inPhase3 = true;
 
             if (!_inPhase3)
@@ -76,7 +76,7 @@ namespace CounterDrone.Core.Algorithms
             else
             {
                 // Phase 3: 高斯扩散
-                float x = windSpeed * (_elapsed - 30f);
+                float x = windSpeed * (_elapsed - (float)_ammo.Phase2Duration);
                 if (x <= 0) return; // 尚未进入有效扩散距离
                 var cls = Kinematics.GetStabilityClass((WeatherType)_env.WeatherType, windSpeed);
                 var sY = Kinematics.SigmaY(cls, x);