refactor(runtime): close simulation ownership

Move remote-motion construction, CreateObject vector initialization, final simulation-component retirement, and the combined J5 ownership ledger into Runtime. Delete App compatibility views and moved-state reconstruction while preserving the existing graphical projection and retail update order.

src/AcDream.Runtime/Physics/RuntimePhysicsState.cs

@@ -12,7 +12,19 @@ public readonly record struct RuntimePhysicsOwnershipSnapshot(
     int CollisionAdmissionCount,
     int CollisionGenerationCount,
     bool OwnsProductionDataCache,
-    bool IsDisposed);
+    bool IsDisposed)
+{
+    public bool IsConverged =>
+        IsDisposed
+        && LandblockCount == 0
+        && RetainedShadowRegistrationCount == 0
+        && SpatialRootCount == 0
+        && SpatialRemoteCount == 0
+        && SpatialProjectileCount == 0
+        && CollisionAdmissionCount == 0
+        && CollisionGenerationCount == 0
+        && OwnsProductionDataCache;
+}
 
 public readonly record struct RuntimePhysicsCellCommit(
     RuntimeEntityRecord Record,
@@ -437,6 +449,8 @@ public sealed class RuntimePhysicsState : IDisposable
                 record,
                 expectedPlacementContract
                     || runtime is IRuntimeRemotePlacement);
+            if (expectedBody is null)
+                InitializeNewPhysicsBody(record, candidateBody);
             Entities.SetRemoteMotion(record, runtime);
             Entities.SetPhysicsBody(record, candidateBody);
             candidateBody.State = record.FinalPhysicsState;
@@ -452,6 +466,52 @@ public sealed class RuntimePhysicsState : IDisposable
         }
     }
 
+    /// <summary>
+    /// Constructs the one built-in remote-motion component for an exact
+    /// canonical incarnation. A graphical host may attach animation and pose
+    /// sinks afterward, but cannot construct or replace simulation state.
+    /// </summary>
+    internal RemoteMotion GetOrCreateRemoteMotion(
+        RuntimeEntityRecord record,
+        Func<bool>? externalOwnerValid = null)
+    {
+        EnsureNotDisposed();
+        ArgumentNullException.ThrowIfNull(record);
+        EnsureCurrent(record);
+        if (record.RemoteMotion is { } retained)
+        {
+            return retained as RemoteMotion
+                ?? throw new InvalidOperationException(
+                    $"Runtime entity 0x{record.ServerGuid:X8}/{record.Incarnation} owns a non-production remote-motion component.");
+        }
+
+        var created = new RemoteMotion(record.PhysicsBody);
+        created.Movement.ActivatePhysicsObject = () =>
+            TryActivateOrdinaryObject(record, created);
+        SetRemoteMotion(record, created, externalOwnerValid);
+        return created;
+    }
+
+    internal bool TryActivateOrdinaryObject(
+        RuntimeEntityRecord record,
+        IRuntimeRemoteMotion runtime,
+        Func<bool>? externalOwnerValid = null)
+    {
+        ArgumentNullException.ThrowIfNull(record);
+        ArgumentNullException.ThrowIfNull(runtime);
+        if (!Entities.IsCurrent(record)
+            || !ReferenceEquals(record.RemoteMotion, runtime)
+            || (record.FinalPhysicsState & PhysicsStateFlags.Static) != 0
+            || !(externalOwnerValid?.Invoke() ?? true))
+        {
+            return false;
+        }
+
+        record.ObjectClock.Activate();
+        runtime.Body.TransientState |= TransientStateFlags.Active;
+        return true;
+    }
+
     /// <summary>
     /// Acquires the one retail <c>CPhysicsObj</c> body for an exact accepted
     /// object incarnation. Factories may cross a host boundary, so ownership
@@ -499,6 +559,7 @@ public sealed class RuntimePhysicsState : IDisposable
                     $"Runtime entity 0x{record.ServerGuid:X8}/{record.Incarnation} acquired two physics bodies within one incarnation.");
             }
 
+            InitializeNewPhysicsBody(record, candidate);
             Entities.SetPhysicsBody(record, candidate);
             candidate.State = record.FinalPhysicsState;
             SynchronizeBodyActiveState(record);
@@ -905,6 +966,7 @@ public sealed class RuntimePhysicsState : IDisposable
     {
         if (_disposed)
             return;
+        Engine.Clear();
         _spatialRemotes.Clear();
         _spatialProjectiles.Clear();
         _spatialRoots.Clear();
@@ -1039,4 +1101,22 @@ public sealed class RuntimePhysicsState : IDisposable
         else
             body.TransientState &= ~TransientStateFlags.Active;
     }
+
+    /// <summary>
+    /// Retail <c>CPhysicsObj::set_description</c> (0x00514F40) installs the
+    /// accepted CreateObject velocity and omega once, when the incarnation's
+    /// CPhysicsObj is first acquired. Later SetState never replays them.
+    /// </summary>
+    private static void InitializeNewPhysicsBody(
+        RuntimeEntityRecord record,
+        PhysicsBody body)
+    {
+        body.State = record.FinalPhysicsState;
+        if (record.Snapshot.Physics is not { } physics)
+            return;
+        if (physics.Velocity is { } velocity && IsFinite(velocity))
+            body.set_velocity(velocity);
+        if (physics.AngularVelocity is { } omega && IsFinite(omega))
+            body.Omega = omega;
+    }
 }