Boss becomes a real fight + readable-but-fair enemy threat

BossState (server-only) + BossAISystem: sole mover, seek -> telegraphed
radial slam (AttackWindup) -> phase-2 speed + swarmer summon. Excluded from
the EnemyAISystem Charger pass; knockback-immune at all 3 stamp sites;
arena-anchored spawn; scaled Health/HitRadius/AttackRange. Grunt windup now
commits in its last ~30% (whiffs out-of-range); Charger stagger roots; grunt
speed 4.2->5.2; swarmer telegraph synced. SweptMove + zone-enemy spawn-stamp
extracted to shared helpers. Zero new [GhostField].

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Assets/_Project/Scripts/Server/Combat/ProjectileDamageSystem.cs

@@ -43,6 +43,11 @@ namespace ProjectM.Server
         /// <summary>RW lookup to stamp server-only knockback on a hit Husk (Husks bake KnockbackState; players/dummies don't).</summary>
         ComponentLookup<KnockbackState> m_KnockbackLookup;
 
+        /// <summary>Read-only lookup so a BOSS (BossState) is skipped by the knockback stamp — the boss is
+        /// knockback-immune (A4) so a solo player can't perma-stunlock it out of its slam wind-ups.</summary>
+        ComponentLookup<BossState> m_BossLookup;
+
+
         /// <summary>Extra forgiveness added to a target's hit radius to approximate the projectile's own size.</summary>
         const float k_ProjectileRadius = 0.2f;
 
@@ -51,6 +56,8 @@ namespace ProjectM.Server
         {
             m_GhostOwnerLookup = state.GetComponentLookup<GhostOwner>(isReadOnly: true);
             m_KnockbackLookup = state.GetComponentLookup<KnockbackState>(isReadOnly: false);
+            m_BossLookup = state.GetComponentLookup<BossState>(isReadOnly: true);
+
 
             // No projectiles → nothing to expire or hit-test; skip the tick (and its allocations) entirely.
             state.RequireForUpdate<Projectile>();
@@ -61,6 +68,8 @@ namespace ProjectM.Server
         {
             m_GhostOwnerLookup.Update(ref state);
             m_KnockbackLookup.Update(ref state);
+            m_BossLookup.Update(ref state);
+
             bool haveTick = SystemAPI.TryGetSingleton<NetworkTime>(out var nt);
 
             float dt = SystemAPI.Time.DeltaTime;
@@ -133,7 +142,7 @@ namespace ProjectM.Server
                         SourceTick = haveTick ? TickUtil.NonZero(nt.ServerTick.TickIndexForValidTick) : 0u,
                     });
                     var hitTarget = targetEntities[bestIdx];
-                    if (haveTick && Tuning.KnockbackSpeed > 0f && m_KnockbackLookup.HasComponent(hitTarget))
+                    if (haveTick && Tuning.KnockbackSpeed > 0f && m_KnockbackLookup.HasComponent(hitTarget) && !m_BossLookup.HasComponent(hitTarget))
                     {
                         m_KnockbackLookup[hitTarget] = new KnockbackState
                         {