feat(streaming): shadow-publish flat collision assets

Carry one immutable prepared collision closure with each accepted near-tier generation and install graph plus flat views through the same retained publication receipt. Apply the same strict package-only rule to live entities, add exact sampled graph-authoritative comparison artifacts and lifecycle counters, and prove cancellation, demotion, rehydrate, revisit, teardown, reconnect, and the nine-stop route with 14,064 zero-mismatch samples.

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

src/AcDream.App/Composition/ContentEffectsAudioComposition.cs

@@ -30,6 +30,7 @@ internal sealed record ContentEffectsAudioResult(
     MagicCatalog MagicCatalog,
     IAnimationLoader AnimationLoader,
     LiveEntityCollisionBuilder CollisionBuilder,
+    LiveCollisionAssetPublisher CollisionAssets,
     EmitterDescRegistry EmitterRegistry,
     ParticleSystem ParticleSystem,
     ParticleHookSink ParticleSink,
@@ -95,6 +96,9 @@ internal interface IContentEffectsAudioCompositionFactory
         IDatReaderWriter dats,
         IAnimationLoader animationLoader,
         bool dumpMotionEnabled);
+    LiveCollisionAssetPublisher CreateLiveCollisionAssetPublisher(
+        PhysicsDataCache physicsData,
+        IPreparedAssetSource preparedAssets);
     EmitterDescRegistry CreateEmitterRegistry(IDatReaderWriter dats);
     ParticleSystem CreateParticleSystem(EmitterDescRegistry emitters);
     ParticleHookSink CreateParticleSink(
@@ -165,6 +169,15 @@ internal sealed class RetailContentEffectsAudioCompositionFactory
                 animationLoader,
                 dumpMotionEnabled));
 
+    public LiveCollisionAssetPublisher CreateLiveCollisionAssetPublisher(
+        PhysicsDataCache physicsData,
+        IPreparedAssetSource preparedAssets) =>
+        new(
+            physicsData,
+            preparedAssets as IPreparedCollisionSource
+                ?? throw new NotSupportedException(
+                    "Production prepared assets must expose collision data."));
+
     public EmitterDescRegistry CreateEmitterRegistry(IDatReaderWriter dats) =>
         new(dats);
 
@@ -332,6 +345,10 @@ internal sealed class ContentEffectsAudioCompositionPhase :
                 _dependencies.DumpMotionEnabled);
             _publication.PublishLiveEntityCollisionBuilder(collision);
             Fault(ContentEffectsAudioCompositionPoint.CollisionBuilderPublished);
+            LiveCollisionAssetPublisher collisionAssets =
+                _factory.CreateLiveCollisionAssetPublisher(
+                    _dependencies.PhysicsDataCache,
+                    preparedAssets);
 
             EmitterDescRegistry emitters = _factory.CreateEmitterRegistry(dats);
             _publication.PublishEmitterRegistry(emitters);
@@ -403,6 +420,7 @@ internal sealed class ContentEffectsAudioCompositionPhase :
                 magic,
                 animations,
                 collision,
+                collisionAssets,
                 emitters,
                 particles,
                 particleSink,