Import art/VFX asset packs + game-feel systems; normalize texture extensions to lowercase for LFS

Add BefourStudios SciFi environment packs, Gabriel Aguiar VFX, and the
ShaderCrew Toon Shader embedded packages, plus combat/enemy/wave/death
gameplay systems and supporting vault docs/screenshots.

Rename 11 vendor textures from uppercase .PNG/.HDR to lowercase so the
case-sensitive Git LFS filters (*.png/*.hdr) match on case-sensitive
filesystems (Linux CI, case-sensitive macOS), not just locally where
core.ignorecase=true masks the gap. Each .meta moved with its asset so
GUID references are preserved. All ~1000 binaries tracked via LFS.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

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

@@ -32,6 +32,7 @@ namespace ProjectM.Server
         public void OnUpdate(ref SystemState state)
         {
             var ecb = new EntityCommandBuffer(Allocator.Temp);
+            bool haveTick = SystemAPI.TryGetSingleton<NetworkTime>(out var netTime);
 
             foreach (var (health, dmg, entity) in
                      SystemAPI.Query<RefRW<Health>, DynamicBuffer<DamageEvent>>()
@@ -40,6 +41,21 @@ namespace ProjectM.Server
                 if (dmg.Length == 0)
                     continue;
 
+                // Respawn invulnerability: a freshly-recovered player ignores damage for a window.
+                if (haveTick && netTime.ServerTick.IsValid && SystemAPI.HasComponent<RespawnInvuln>(entity))
+                {
+                    uint until = SystemAPI.GetComponent<RespawnInvuln>(entity).UntilTick;
+                    if (until != 0)
+                    {
+                        var untilTick = new NetworkTick(until);
+                        if (untilTick.IsValid && untilTick.IsNewerThan(netTime.ServerTick))
+                        {
+                            dmg.Clear();
+                            continue;
+                        }
+                    }
+                }
+
                 float total = 0f;
                 for (int i = 0; i < dmg.Length; i++)
                     total += dmg[i].Amount;
@@ -57,7 +73,7 @@ namespace ProjectM.Server
                 health.ValueRW.Current = newHp;
 
                 // Server-authoritative death: training dummies despawn; player death is deferred (clamp only).
-                if (health.ValueRO.Current <= 0f && SystemAPI.HasComponent<TrainingDummyTag>(entity))
+                if (health.ValueRO.Current <= 0f && (SystemAPI.HasComponent<TrainingDummyTag>(entity) || SystemAPI.HasComponent<EnemyTag>(entity)))
                     ecb.DestroyEntity(entity);
             }