perf(vfx): port retail particle visibility degradation

Resolve DAT-authored particle ranges from the hardware GfxObj, apply retail distance and completed-cell visibility gates, and preserve the exact finite/infinite off-view update semantics. This removes dense-world simulation work without shortening terrain, entity, fog, or streaming distance.

Publish doorway-clipped outdoor cells through a focused frame controller, retain effect cell identity for outdoor statics, reject hidden emitters before particle-slot scans, and offer an explicit opt-in Extended particle range.

Release build succeeds and all 5,857 tests pass with five intentional skips. Retail-conformance, architecture, and adversarial review cycles are clean; connected Aerlinthe visual/performance gate pending.

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

tests/AcDream.Core.Tests/Vfx/ParticleHookSinkTests.cs

@@ -316,6 +316,8 @@ public sealed class ParticleHookSinkTests
         Assert.True(emitter.PresentationVisible);
         Assert.Equal(spawnedAt, emitter.Particles[0].SpawnedAt);
 
+        system.Tick(0.01f);
+        Assert.Equal(1, system.ActiveEmitterCount);
         system.Tick(0.01f);
         Assert.Equal(0, system.ActiveEmitterCount);
     }
@@ -336,6 +338,30 @@ public sealed class ParticleHookSinkTests
         Assert.Equal(1, deathNotices);
     }
 
+    [Fact]
+    public void ExaminationObjectPolicyAppliesToExistingAndFutureEmittersAndTearsDown()
+    {
+        const uint emitterId = 0x32000058u;
+        var (system, sink, _) = Harness(emitterId);
+        sink.OnHook(Owner, Vector3.Zero, Create(emitterId, logicalId: 21u));
+
+        sink.SetEntityExaminationObject(Owner, true);
+        Assert.Equal(
+            ParticleVisibilityPolicy.Examination,
+            Assert.Single(system.EnumerateEmitters()).VisibilityPolicy);
+
+        sink.OnHook(Owner, Vector3.Zero, Create(emitterId, logicalId: 22u));
+        Assert.All(
+            system.EnumerateEmitters(),
+            emitter => Assert.Equal(
+                ParticleVisibilityPolicy.Examination,
+                emitter.VisibilityPolicy));
+        Assert.Equal(1, sink.ExaminationOwnerCount);
+
+        sink.StopAllForEntity(Owner, fadeOut: false);
+        Assert.Equal(0, sink.ExaminationOwnerCount);
+    }
+
     private sealed class MutablePoseSource : IEntityEffectPoseSource
     {
         private readonly Dictionary<uint, (Matrix4x4 Root, Matrix4x4[] Parts)> _poses = new();