refactor(world): extract live entity network updates

Move Position, Vector, State, Movement, and equal-generation CreateObject routing out of GameWindow while preserving per-channel authority, ForcePosition acknowledgement, and motion-runtime ownership. Add adversarial authority and exact-wire coverage so reentrant updates and GUID reuse cannot publish stale state.

src/AcDream.App/Physics/DeferredLiveEntityMotionRuntimeBindings.cs

@@ -0,0 +1,64 @@
+using AcDream.App.Physics;
+using AcDream.App.Rendering;
+using AcDream.Core.Net;
+using AcDream.Core.Physics.Motion;
+using AcDream.Core.World;
+
+namespace AcDream.App.Physics;
+
+/// <summary>
+/// Narrow reverse seam for collaborators constructed before the live network
+/// owner. It carries no state or identity: every call resolves the one bound
+/// update-thread owner, and use before bind fails immediately.
+/// </summary>
+internal interface ILiveEntityMotionRuntimeBindings
+{
+    (float Radius, float Height) GetSetupCylinder(uint serverGuid, WorldEntity entity);
+    bool RouteServerMoveTo(
+        MovementManager movement,
+        uint cellId,
+        WorldSession.EntityMotionUpdate update);
+    void StickToObjectFromWire(IPhysicsObjHost? host, uint targetGuid);
+    void ClearTargetForHiddenEntity(uint serverGuid);
+    IPhysicsObjHost? ResolvePhysicsHost(uint serverGuid);
+}
+
+internal sealed class DeferredLiveEntityMotionRuntimeBindings
+    : ILiveEntityMotionRuntimeBindings
+{
+    private ILiveEntityMotionRuntimeBindings? _target;
+
+    public void Bind(ILiveEntityMotionRuntimeBindings target)
+    {
+        ArgumentNullException.ThrowIfNull(target);
+        if (_target is not null)
+        {
+            throw new InvalidOperationException(
+                "Live entity motion runtime bindings are already bound.");
+        }
+        _target = target;
+    }
+
+    private ILiveEntityMotionRuntimeBindings Target =>
+        _target ?? throw new InvalidOperationException(
+            "Live entity motion runtime bindings were used before binding.");
+
+    public (float Radius, float Height) GetSetupCylinder(
+        uint serverGuid,
+        WorldEntity entity) => Target.GetSetupCylinder(serverGuid, entity);
+
+    public bool RouteServerMoveTo(
+        MovementManager movement,
+        uint cellId,
+        WorldSession.EntityMotionUpdate update) =>
+        Target.RouteServerMoveTo(movement, cellId, update);
+
+    public void StickToObjectFromWire(IPhysicsObjHost? host, uint targetGuid) =>
+        Target.StickToObjectFromWire(host, targetGuid);
+
+    public void ClearTargetForHiddenEntity(uint serverGuid) =>
+        Target.ClearTargetForHiddenEntity(serverGuid);
+
+    public IPhysicsObjHost? ResolvePhysicsHost(uint serverGuid) =>
+        Target.ResolvePhysicsHost(serverGuid);
+}