fix: CalcRoundsNeeded=ceil(requiredCoverage/2R),去除+1 hardcode

- 理论：所有云在无人机到达时膨胀到expansionTime≈30s，半径均匀
- ceil(333.3/40.4)=9发覆盖363m/6.54s>6s
- hp=0.10来自tick离散(步长22m,云径40m,每云1-2采样点)

src/CounterDrone.Core/Algorithms/DefaultDefensePlanner.cs

@@ -397,6 +397,14 @@ namespace CounterDrone.Core.Algorithms
             float singleCoverage = neededExposure * avgSpeed;
             float requiredCoverage = singleCoverage;
 
+            return Math.Max(1,
+                (int)Math.Ceiling(requiredCoverage / spacing));
+
+            var aerosolType = (AerosolType)ammo.AerosolType;
+            float neededExposure = aerosolType == AerosolType.ActiveMaterial ? 2f : 6f;
+            float singleCoverage = neededExposure * avgSpeed;
+            float requiredCoverage = singleCoverage;
+
             return Math.Max(1,
                 (int)Math.Ceiling((requiredCoverage - 2f * turbulentRadius) / spacing) + 1);
         }