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/SessionPlayerComposition.cs

@@ -12,6 +12,7 @@ using AcDream.App.Settings;
 using AcDream.App.Streaming;
 using AcDream.App.Update;
 using AcDream.App.World;
+using AcDream.Content;
 using AcDream.Core.Combat;
 using AcDream.Core.Items;
 using AcDream.Core.Chat;
@@ -252,11 +253,16 @@ internal sealed class SessionPlayerCompositionPhase
             $"(window={2 * farRadius + 1}x{2 * farRadius + 1})");
         Fault(SessionPlayerCompositionPoint.StreamingRadiiResolved);
 
+        IPreparedCollisionSource preparedCollisions =
+            content.PreparedAssets as IPreparedCollisionSource ??
+            throw new NotSupportedException(
+                "Production prepared assets must expose the matching " +
+                "prepared-collision catalog.");
         var landblockBuildFactory = new LandblockBuildFactory(
             content.Dats,
+            preparedCollisions,
             d.DatLock,
             world.TerrainBuild.HeightTable,
-            d.PhysicsDataCache,
             d.Options.DumpSceneryZ);
         var streamerLease = scope.Acquire(
             "landblock streamer",
@@ -399,7 +405,7 @@ internal sealed class SessionPlayerCompositionPhase
             d.Options,
             content.Dats,
             live.LiveEntities,
-            d.PhysicsDataCache,
+            content.CollisionAssets,
             content.AnimationLoader,
             live.EntitySpawnAdapter,
             world.Foundation.TextureCache,
@@ -689,7 +695,7 @@ internal sealed class SessionPlayerCompositionPhase
             d.MotionBindings,
             content.Dats,
             d.DatLock,
-            d.PhysicsDataCache,
+            content.CollisionAssets,
             d.AnimatedEntities,
             localPlayerAnimation,
             localPlayerShadow,