checkpoint(render): G2 owner findings — terrain punch assigned to S4, portal-haze probe

Owner G2 check at 4b0b29e4: Facility Hub PASS, Holtburg house PASS,
cathedral leak unchanged (S3/S4). Two new findings:
- doorway-sized fragments of houses on the terrace below show through
  the hill in Holtburg: PortalDepthMaskRenderer draws every visited cell's
  exit-portal fan with depth compare Always + write, so a doorway behind
  terrain still punches far depth through it. Pre-existing; S4 owns the
  punch (ledger row updated).
- the purple UnHide haze (script type 0x75, played on the retail
  Hidden->visible physics-state edge) no longer shows on the local player
  after a portal. Under investigation: temporary print-only traces
  [pes-spawn]/[pes-vis] under ACDREAM_DUMP_PLAYSCRIPT=1 (launch-options row
  amended; both die with the investigation) and a timed arrival route
  tools/overhaul-selfgate/route-portal-haze.txt.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/AcDream.Core/Vfx/ParticleSystem.cs

@@ -860,11 +860,25 @@ public sealed class ParticleSystem : IParticleSystem
         }
     }
 
+    /// <summary>TEMPORARY (2026-09-03 portal-haze investigation, dies with
+    /// it): print-only trace of renderable-index flips, wired under
+    /// <c>ACDREAM_DUMP_PLAYSCRIPT=1</c> beside the hook sink's trace.</summary>
+    public Action<string>? DiagnosticSink { get; set; }
+
+    private static readonly bool DiagEnabled =
+        Environment.GetEnvironmentVariable("ACDREAM_DUMP_PLAYSCRIPT") == "1";
+
     private void RefreshRenderableIndex(ParticleEmitter emitter, bool wasRenderable)
     {
         bool isRenderable = IsRenderable(emitter);
         if (wasRenderable == isRenderable)
             return;
+        if (DiagEnabled)
+            DiagnosticSink?.Invoke(
+            $"[pes-vis] handle={emitter.Handle} owner=0x{emitter.AttachedObjectId:X8} "
+            + $"cell=0x{emitter.OwnerCellId:X8} renderable={isRenderable} "
+            + $"viewEligible={emitter.ViewEligible} presentationVisible={emitter.PresentationVisible} "
+            + $"pass={emitter.RenderPass}");
 
         SortedSet<int> index =
             _renderableHandlesByPass[RenderPassIndex(emitter.RenderPass)];