Phase 1 B3: enemies die with a corpse window instead of popping out of existence

Server: HealthApplyDamageSystem marks EnemyTag Dying{UntilTick} (TickUtil.
NonZero, ~54 ticks) on the lethal 0-crossing instead of instant destroy,
zeroes every live cue (replicated AttackWindup, LungeState + IsLunging bit,
KnockbackState), destroys on expiry; plain-world tests keep instant destroy
(no NetworkTime) so the suite's assertions stay meaningful.

Every consumer now ignores corpses (all confirmed entity-count/unfiltered by
the design review): EnemyAISystem all 4 passes, BossAISystem brain + summon
cap, RoomEnemyDirector room-clear + MaxAlive fit, WaveSystem cap + cleared,
CyclePhaseSystem breach wipe + DefendCleared, ThreatDirector timeout cull,
TurretFire targeting, CoreDamage drain, ProjectileDamage snapshot (corpses
are not shields), AbilityFire auto-aim candidates, debug cull + telemetry.
Wipe passes skip Dying to avoid cross-ECB double-destroys.

Client: EnemyAnimationDriveSystem finally drives the controller's IsDead
param (Health.Current<=0 is the replicated death read; corpse locomotion
zeroed); CombatFeedbackSystem moves the kill CRUNCH to the 0-crossing (the
prune-edge timing would land it ~1 s late) - the prune keeps a small
dissolve puff for corpses and the legacy full read for alive-vanish culls.

456/456 EditMode.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Assets/_Project/Scripts/Simulation/Combat/AbilityFireSystem.cs

@@ -82,8 +82,9 @@ namespace ProjectM.Simulation
                 foreach (var (tx, th, te) in
                          SystemAPI.Query<RefRO<LocalTransform>, RefRO<Health>>().WithAny<TrainingDummyTag, EnemyTag>().WithEntityAccess())
                 {
+                    if (th.ValueRO.Current <= 0f) continue; // B3: corpses are neither aim magnets nor cleave targets
                     candidatePositions.Add(tx.ValueRO.Position);
-                    if (th.ValueRO.Current > 0f) { coneTargets.Add(te); coneTargetPos.Add(tx.ValueRO.Position); }
+                    coneTargets.Add(te); coneTargetPos.Add(tx.ValueRO.Position);
                 }
             }
             var candidates = candidatePositions.AsArray();

Assets/_Project/Scripts/Simulation/Combat/Dying.cs

@@ -0,0 +1,19 @@
+using Unity.Entities;
+
+namespace ProjectM.Simulation
+{
+    /// <summary>
+    /// Phase 1 (B3): the enemy corpse window. Stamped ONCE by <c>HealthApplyDamageSystem</c> on the lethal
+    /// 0-crossing (server-only, never replicated — clients derive the death read from the replicated
+    /// <c>Health.Current&lt;=0</c>); the entity is destroyed when ServerTick reaches <see cref="UntilTick"/>.
+    /// While present the enemy is a CORPSE: every actor pass (AI move/windup/contact, boss kit), every
+    /// LIVING count (room clear, HUD Remaining, MaxAlive fit, summon cap, siege cleared) and every target
+    /// snapshot (projectiles, melee, turrets, auto-aim, aggro) must skip it — a corpse neither acts, counts,
+    /// nor soaks hits (design review wf_fd177263: all counts were entity-count based, all snapshots unfiltered).
+    /// </summary>
+    public struct Dying : IComponentData
+    {
+        /// <summary>Server tick the corpse despawns (via <c>TickUtil.NonZero</c>; compared via <c>NetworkTick</c>).</summary>
+        public uint UntilTick;
+    }
+}

Assets/_Project/Scripts/Simulation/Combat/Dying.cs.meta

@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: 3b794b215be5185499725afc93d9d78c