refactor(runtime): own per-session physics simulation

Move the sole PhysicsEngine, production cache, collision admissions, canonical bodies and hosts, remote components, ordinary/remote worksets, simulation, cell commits, and shadow synchronization under RuntimeEntityObjectLifetime. Keep App as the prepared-asset, animation-input, and render-projection adapter while preserving the named-retail update and collision order.

Add exact-incarnation, object-clock, callback-reentrancy, GUID-reuse, two-runtime isolation, source ownership, collision publication, and graphical projection coverage. Release build and the complete 8,588-test solution pass.

Co-authored-by: Codex <noreply@openai.com>

src/AcDream.Runtime/Entities/RuntimeEntityDirectory.cs

@@ -1,5 +1,6 @@
 using AcDream.Core.Net;
 using AcDream.Core.Physics;
+using AcDream.Runtime.Physics;
 
 namespace AcDream.Runtime.Entities;
 
@@ -338,6 +339,30 @@ public sealed class RuntimeEntityDirectory
         record.PhysicsBodyAcquisitionInProgress = value;
     }
 
+    public void SetRemoteMotion(
+        RuntimeEntityRecord record,
+        IRuntimeRemoteMotion? remote)
+    {
+        EnsureKnown(record);
+        record.RemoteMotion = remote;
+    }
+
+    public void SetRemoteMotionBindingInProgress(
+        RuntimeEntityRecord record,
+        bool value)
+    {
+        EnsureKnown(record);
+        record.RemoteMotionBindingInProgress = value;
+    }
+
+    public void SetRequiresRemotePlacementRuntime(
+        RuntimeEntityRecord record,
+        bool value)
+    {
+        EnsureKnown(record);
+        record.RequiresRemotePlacementRuntime = value;
+    }
+
     public void SetPhysicsHost(
         RuntimeEntityRecord record,
         AcDream.Core.Physics.Motion.IPhysicsObjHost? host)

src/AcDream.Runtime/Entities/RuntimeEntityObjectLifetime.cs

@@ -2,6 +2,7 @@ using AcDream.Core.Items;
 using AcDream.Core.Net;
 using AcDream.Core.Net.Messages;
 using AcDream.Core.Physics;
+using AcDream.Runtime.Physics;
 
 namespace AcDream.Runtime.Entities;
 
@@ -74,6 +75,21 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
         uint firstLocalEntityId = RuntimeEntityDirectory.FirstLocalEntityId)
     {
         Entities = new RuntimeEntityDirectory(firstLocalEntityId);
+        Physics = new RuntimePhysicsState(Entities);
+        Objects = new ClientObjectTable();
+        var views = new RuntimeEntityObjectViews(Entities, Objects);
+        EntityView = views.Entities;
+        InventoryView = views.Inventory;
+        Events = new RuntimeEntityObjectEventStream(Entities, Objects);
+    }
+
+    internal RuntimeEntityObjectLifetime(
+        PhysicsDataCache physicsDataCache,
+        uint firstLocalEntityId = RuntimeEntityDirectory.FirstLocalEntityId)
+    {
+        ArgumentNullException.ThrowIfNull(physicsDataCache);
+        Entities = new RuntimeEntityDirectory(firstLocalEntityId);
+        Physics = new RuntimePhysicsState(Entities, physicsDataCache);
         Objects = new ClientObjectTable();
         var views = new RuntimeEntityObjectViews(Entities, Objects);
         EntityView = views.Entities;
@@ -82,6 +98,7 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
     }
 
     public RuntimeEntityDirectory Entities { get; }
+    public RuntimePhysicsState Physics { get; }
     public ClientObjectTable Objects { get; }
     public IRuntimeEntityView EntityView { get; }
     public IRuntimeInventoryView InventoryView { get; }
@@ -324,6 +341,10 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
             Entities.RetainTeardown(canonical);
             try
             {
+                Physics.RemoveSpatialProjection(canonical);
+                Entities.SetRemoteMotion(canonical, null);
+                Entities.SetRemoteMotionBindingInProgress(canonical, false);
+                Entities.SetRequiresRemotePlacementRuntime(canonical, false);
                 Entities.SetPhysicsHost(canonical, null);
                 Entities.SetPhysicsBody(canonical, null);
                 Entities.SetPhysicsBodyAcquisitionInProgress(canonical, false);
@@ -960,6 +981,7 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
         {
             _disposed = true;
             Events.Dispose();
+            Physics.Dispose();
         }
 
         if (failures is not null)

src/AcDream.Runtime/Entities/RuntimeEntityRecord.cs

@@ -1,5 +1,6 @@
 using AcDream.Core.Net;
 using AcDream.Core.Physics;
+using AcDream.Runtime.Physics;
 
 namespace AcDream.Runtime.Entities;
 
@@ -68,6 +69,9 @@ public sealed class RuntimeEntityRecord
     public bool HasPartArray { get; internal set; }
     public PhysicsBody? PhysicsBody { get; internal set; }
     public bool PhysicsBodyAcquisitionInProgress { get; internal set; }
+    public IRuntimeRemoteMotion? RemoteMotion { get; internal set; }
+    public bool RemoteMotionBindingInProgress { get; internal set; }
+    public bool RequiresRemotePlacementRuntime { get; internal set; }
     public AcDream.Core.Physics.Motion.IPhysicsObjHost? PhysicsHost { get; internal set; }
     public ulong PositionAuthorityVersion { get; private set; }
     public ulong StateAuthorityVersion { get; private set; }