fix: 空基 FireEvent.MuzzleVelocity=0 + 空基弹道单元测试

- GenerateFireEventsAt: 空基时 MuzzleVelocity=0（而非800）
- 新增 AirBased_FireTime_EarlierThanArrival 验证提前量
- 新增 AirBased_FireTime_EarlierThanGroundBased 验证空基更早
- 新增 AirBased_NoMuzzleVelocityInFireEvent 验证 MuzzleVelocity=0
- 空基弹道计算本身正确（recommendedTiming - flightTime - fallTime）

src/CounterDrone.Core/Algorithms/DefaultDefensePlanner.cs

@@ -438,7 +438,7 @@ namespace CounterDrone.Core.Algorithms
                 TargetX = tx,
                 TargetY = mid.Y,
                 TargetZ = tz,
-                MuzzleVelocity = unit.MuzzleVelocity,
+                MuzzleVelocity = unit.Type == PlatformType.AirBased ? 0f : unit.MuzzleVelocity,
             });
 
             return events;

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

@@ -234,7 +234,7 @@ namespace CounterDrone.Core.Tests
         }
 
         // ═══════════════════════════════════════
-        // 空基
+        // 空基弹道
         // ═══════════════════════════════════════
 
         [Fact]
@@ -251,6 +251,68 @@ namespace CounterDrone.Core.Tests
             Assert.True(result.Best.ThreatsEngaged > 0);
         }
 
+        [Fact]
+        public void AirBased_FireTime_EarlierThanArrival()
+        {
+            // 空基需要飞行+下落时间，发射应远早于到达时间
+            var units = new List<FireUnit>
+            {
+                new FireUnit { Id = "u0", Type = PlatformType.AirBased,
+                    Position = new Vector3(3000, 2500, -2000), GunCount = 4, ChannelsPerGun = 4,
+                    CruiseSpeed = 55, ReleaseAltitude = 1500, TotalMunitions = 16,
+                    AmmoTypes = new() { AerosolType.InertGas } },
+            };
+            var threat = MakeThreat(PowerType.Piston, 120);
+            var result = new DefaultDefensePlanner(TestAmmo).Plan(units, new() { threat }, new CombatScene());
+            float arrivalTime = threat.GetArrivalTime();
+            // 空基至少需要 (飞行距离/55 + 下落时间) 的提前量
+            float minAdvance = 20f; // 至少提前 20 秒
+            Assert.All(result.Best.MergedSchedule, fe =>
+                Assert.True(fe.FireTime < arrivalTime - minAdvance,
+                    $"空基FireTime={fe.FireTime:F1}, arrival={arrivalTime:F1}, 应至少提前{minAdvance}s"));
+        }
+
+        [Fact]
+        public void AirBased_FireTime_EarlierThanGroundBased()
+        {
+            // 同样威胁，空基应比地基更早发射（需要飞行时间）
+            var threat = MakeThreat(PowerType.Piston, 120);
+            var airUnits = new List<FireUnit>
+            {
+                new FireUnit { Id = "u0", Type = PlatformType.AirBased,
+                    Position = new Vector3(3000, 2500, -2000), GunCount = 4, ChannelsPerGun = 4,
+                    CruiseSpeed = 55, ReleaseAltitude = 1500, TotalMunitions = 16,
+                    AmmoTypes = new() { AerosolType.InertGas } },
+            };
+            var groundUnits = MakeGroundUnits(1);
+
+            var airResult = new DefaultDefensePlanner(TestAmmo).Plan(airUnits, new() { threat }, new CombatScene());
+            var groundResult = new DefaultDefensePlanner(TestAmmo).Plan(groundUnits, new() { threat }, new CombatScene());
+
+            float airFirst = airResult.Best.MergedSchedule.Min(e => e.FireTime);
+            float groundFirst = groundResult.Best.MergedSchedule.Min(e => e.FireTime);
+            Assert.True(airFirst < groundFirst,
+                $"空基首发射={airFirst:F1}s, 地基首发射={groundFirst:F1}s, 空基应更早");
+        }
+
+        [Fact]
+        public void AirBased_NoMuzzleVelocityInFireEvent()
+        {
+            // 空基 FireEvent 的 MuzzleVelocity 应为 0（不适用）
+            var units = new List<FireUnit>
+            {
+                new FireUnit { Id = "u0", Type = PlatformType.AirBased,
+                    Position = new Vector3(3000, 2500, -2000), GunCount = 4, ChannelsPerGun = 4,
+                    CruiseSpeed = 55, ReleaseAltitude = 1500, TotalMunitions = 16,
+                    AmmoTypes = new() { AerosolType.InertGas } },
+            };
+            var threat = MakeThreat(PowerType.Piston, 120);
+            var result = new DefaultDefensePlanner(TestAmmo).Plan(units, new() { threat }, new CombatScene());
+            Assert.All(result.Best.MergedSchedule, fe =>
+                Assert.True(fe.MuzzleVelocity < 10f,
+                    $"空基 MuzzleVelocity={fe.MuzzleVelocity}, 应≈0"));
+        }
+
         // ═══════════════════════════════════════
         // 集成验证
         // ═══════════════════════════════════════