feat(render): S2 chunk 6 — particle emitters draw by their own cell (add_particle_shadow_to_cell)

Owner G2 finding: the purple cloud around an arriving character no longer
drew. The server keeps the player Hidden until acdream sends LoginComplete at
reveal completion (retail-correct); the Hidden-state script's emitters spawn
in the arrival cell and are view-eligible when the world appears, but the
walk drew an owner's emitters only through the owner's registry rows, and a
hidden owner's shadow is suspended. Retail's
CPhysicsObj::add_particle_shadow_to_cell (0x00514a70) gives an emitter one
shadow in its OWN current cell, drawn at that cell's turn regardless of the
parent's hidden state (add_shadows_to_cells 0x00514aed skips the flood for
state & 0x1000).

Port: ParticleSystem keeps a per-pass cell -> renderable-handles index
(maintained at every renderable/OwnerCellId change) and
CopyRenderableEmittersInCell; ParticleRenderer.DrawForCell; the walk draws
particles BY CELL at the existing turns (interior CellParticles, landscape
LandscapeCellParticles), the events fire for every visited cell, and every
owner-union particle path is deleted (UnionOwners/UnionNewOwners for
particles, the outdoor drawn-owner dedupe, the executor's owner
classification sets, the context ParticleOwnerIds members). The post-replay
per-cell pass double-submitted the root flood's emitters and is deleted: an
emitter draws once, at its cell's replay turn. AD-117 item 4 becomes a port
note (the index lives in the particle system; an emitter is not a physics
object in acdream). The temporary [pes-spawn]/[pes-vis] traces are removed
and the ACDREAM_DUMP_PLAYSCRIPT row restored.

Verified: timed arrival route logs/selfgate-20260903-062522-haze-chunk6,
frame h02-arrive-400ms shows the cloud at the character in Facility Hub.
Gates (Release): Core 4,987/4,987; Content 214/214; Runtime 1,884/1,884; App
hermetic lane 6,760/6,760; App InstalledDat 217 pass / 2 pre-existing #383.

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

src/AcDream.App/World/LiveEntityPresentationController.cs

@@ -21,9 +21,6 @@ public sealed class LiveEntityPresentationController : IDisposable
     public const uint UnHideScriptType = 0x75u;
     public const uint HiddenScriptType = 0x76u;
 
-    private static readonly bool HiddenTraceEnabled =
-        Environment.GetEnvironmentVariable("ACDREAM_DUMP_PLAYSCRIPT") == "1";
-
     private readonly LiveEntityRuntime _liveEntities;
     private readonly ShadowObjectRegistry _shadows;
     private readonly Func<uint, uint, float, bool> _playTyped;