fix(rendering): synchronize hidden live projections

Inbound state continues while portal reveal blocks ordinary world simulation. Synchronize only the derived render projection after those hidden-frame network and command phases so the first revealed draw cannot observe a stale live transform, without advancing effects, particles, attachments, or lights.

src/AcDream.App/Composition/FrameRootComposition.cs

@@ -517,7 +517,8 @@ internal sealed class FrameRootCompositionPhase
             session.LiveSession,
             session.LocalPlayerFrame,
             session.LiveSpatialReconciler,
-            live.WorldAvailability);
+            live.WorldAvailability,
+            live.RenderSceneShadow?.LiveProjections);
         var cameraFrame = new CameraFrameController(
             host.CameraController,
             d.InputCapture,

src/AcDream.App/Rendering/Scene/LiveRenderProjectionJournal.cs

@@ -1,16 +1,16 @@
+using AcDream.App.Update;
 using AcDream.App.World;
 using AcDream.Core.World;
 
 namespace AcDream.App.Rendering.Scene;
 
-internal interface ILiveRenderProjectionSink
+internal interface ILiveRenderProjectionSink : IRenderProjectionSyncPhase
 {
     bool OnEntityReady(LiveEntityReadyCandidate candidate);
     void OnProjectionVisibilityChanged(LiveEntityRecord record, bool visible);
     void OnProjectionPoseReady(uint serverGuid);
     void OnProjectionRemoved(uint localEntityId);
     void OnResourceUnregister(WorldEntity entity);
-    void SynchronizeActiveSources();
 }
 
 /// <summary>

src/AcDream.App/Update/LiveObjectFrameController.cs

@@ -34,6 +34,17 @@ internal interface ILiveSpatialReconcilePhase
     void Reconcile();
 }
 
+/// <summary>
+/// Keeps the derived render projection synchronized after inbound mutation
+/// while normal world simulation/presentation is blocked by portal reveal.
+/// This is deliberately narrower than full spatial reconciliation: hidden
+/// frames must not advance particles, effects, attachments, or lights.
+/// </summary>
+internal interface IRenderProjectionSyncPhase
+{
+    void SynchronizeActiveSources();
+}
+
 internal interface IParticleRangeSource
 {
     float RangeMultiplier { get; }

src/AcDream.App/World/RetailLiveFrameCoordinator.cs

@@ -25,6 +25,7 @@ internal sealed class RetailLiveFrameCoordinator : IRetailLiveFramePhase
     private readonly IPostNetworkCommandFramePhase _localPlayer;
     private readonly ILiveSpatialReconcilePhase _spatialReconciler;
     private readonly IWorldGenerationAvailability _availability;
+    private readonly IRenderProjectionSyncPhase? _renderProjectionSync;
 
     public RetailLiveFrameCoordinator(
         ILiveObjectFramePhase objects,
@@ -32,7 +33,8 @@ internal sealed class RetailLiveFrameCoordinator : IRetailLiveFramePhase
         ILiveSessionFramePhase session,
         IPostNetworkCommandFramePhase localPlayer,
         ILiveSpatialReconcilePhase spatialReconciler,
-        IWorldGenerationAvailability? availability = null)
+        IWorldGenerationAvailability? availability = null,
+        IRenderProjectionSyncPhase? renderProjectionSync = null)
     {
         _objects = objects ?? throw new ArgumentNullException(nameof(objects));
         _worldState = worldState ?? throw new ArgumentNullException(nameof(worldState));
@@ -41,6 +43,7 @@ internal sealed class RetailLiveFrameCoordinator : IRetailLiveFramePhase
         _spatialReconciler = spatialReconciler
             ?? throw new ArgumentNullException(nameof(spatialReconciler));
         _availability = availability ?? AlwaysAvailableWorldGeneration.Instance;
+        _renderProjectionSync = renderProjectionSync;
     }
 
     public void Tick(float deltaSeconds)
@@ -53,6 +56,8 @@ internal sealed class RetailLiveFrameCoordinator : IRetailLiveFramePhase
         _localPlayer.RunPostNetworkCommandPhase();
         if (_availability.IsWorldAvailable)
             _spatialReconciler.Reconcile();
+        else
+            _renderProjectionSync?.SynchronizeActiveSources();
     }
 
     public static double NormalizeDeltaSeconds(double deltaSeconds) =>

tests/AcDream.App.Tests/FramePhaseTestDoubles.cs

@@ -25,3 +25,9 @@ internal sealed class TestLiveSpatialReconcilePhase(Action reconcile)
 {
     public void Reconcile() => reconcile();
 }
+
+internal sealed class TestRenderProjectionSyncPhase(Action synchronize)
+    : IRenderProjectionSyncPhase
+{
+    public void SynchronizeActiveSources() => synchronize();
+}

tests/AcDream.App.Tests/World/RecallTeleportAnimationTests.cs

@@ -57,6 +57,31 @@ public sealed class RecallTeleportAnimationTests
         Assert.Equal(["network", "commands"], calls);
     }
 
+    [Fact]
+    public void LiveFrame_WhileCellsAreBlocked_SynchronizesOnlyRenderProjection()
+    {
+        var calls = new List<string>();
+        var availability = new WorldGenerationAvailabilityState();
+        availability.Begin(1);
+        var frame = new RetailLiveFrameCoordinator(
+            new TestLiveObjectFramePhase(_ => calls.Add("objects")),
+            new GpuWorldState(availability: availability),
+            new TestLiveSessionFramePhase(() => calls.Add("network")),
+            new TestPostNetworkCommandFramePhase(
+                () => calls.Add("commands")),
+            new TestLiveSpatialReconcilePhase(
+                () => calls.Add("spatial")),
+            availability,
+            new TestRenderProjectionSyncPhase(
+                () => calls.Add("render-projection")));
+
+        frame.Tick(1f / 60f);
+
+        Assert.Equal(
+            ["network", "commands", "render-projection"],
+            calls);
+    }
+
     [Fact]
     public void LiveFrame_InvalidHostDeltaCannotBlockNetworkDispatch()
     {