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.App/Physics/ShadowPositionSynchronizer.cs

@@ -1,39 +0,0 @@
-using System.Numerics;
-using AcDream.Core.Physics;
-
-namespace AcDream.App.Physics;
-
-/// <summary>
-/// Shared host adapter for retail's moved-object shadow re-registration
-/// (<c>CPhysicsObj::SetPositionInternal</c> 0x00515330). Both the local body
-/// and remote dead-reckoning bodies publish their resolved position through
-/// this one cell-offset calculation.
-/// </summary>
-internal static class ShadowPositionSynchronizer
-{
-    public static void Sync(
-        ShadowObjectRegistry registry,
-        uint entityId,
-        Vector3 position,
-        Quaternion orientation,
-        uint cellId,
-        int liveCenterX,
-        int liveCenterY)
-    {
-        if (cellId == 0)
-            return;
-
-        int landblockX = (int)((cellId >> 24) & 0xFFu);
-        int landblockY = (int)((cellId >> 16) & 0xFFu);
-        float worldOffsetX = (landblockX - liveCenterX) * 192f;
-        float worldOffsetY = (landblockY - liveCenterY) * 192f;
-        registry.UpdatePosition(
-            entityId,
-            position,
-            orientation,
-            worldOffsetX,
-            worldOffsetY,
-            cellId,
-            seedCellId: cellId);
-    }
-}