feat(wb): [indoor-upload] probe for EnvCell mesh requests + completions

Instruments WbMeshAdapter at two sites:
- IncrementRefCount: on first call for an EnvCell id (low 16 bits >=
  0x0100), tag the id in _pendingEnvCellRequests and log
  [indoor-upload] requested.
- Tick: when WB's StagedMeshData drains an ObjectMeshData whose
  ObjectId matches a pending EnvCell, log [indoor-upload] completed
  with parts count, EnvCellGeometry vertex count, and upload result.

Missing "completed" lines after "requested" identify hypothesis H1
(WB silently returns null from PrepareEnvCellMeshData).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/AcDream.App/Rendering/Wb/WbMeshAdapter.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using AcDream.Core.Meshing;
+using AcDream.Core.Rendering;
 using Chorizite.OpenGLSDLBackend;
 using Chorizite.OpenGLSDLBackend.Lib;
 using DatReaderWriter;
@@ -34,6 +35,15 @@ public sealed class WbMeshAdapter : IDisposable, IWbMeshAdapter
     private readonly AcSurfaceMetadataTable _metadataTable = new();
     private readonly HashSet<ulong> _metadataPopulated = new();
 
+    /// <summary>
+    /// EnvCell ids we've requested via PrepareMeshDataAsync but not yet
+    /// seen completion for in Tick(). Used by the [indoor-upload] probe
+    /// to log requested + completed pairs. Cleared per completion;
+    /// missing completions after a few seconds indicate WB silently
+    /// returned null (hypothesis H1 in the design spec).
+    /// </summary>
+    private readonly HashSet<ulong> _pendingEnvCellRequests = new();
+
     /// <summary>
     /// True when this instance was created via <see cref="CreateUninitialized"/>;
     /// all public methods no-op when uninitialized.
@@ -134,6 +144,13 @@ public sealed class WbMeshAdapter : IDisposable, IWbMeshAdapter
             // per-part GfxObj ids (0x01XXXXXX). WB's Setup-expansion path is
             // unused.
             _ = _meshManager.PrepareMeshDataAsync(id, isSetup: false);
+
+            // [indoor-upload] requested probe — only for EnvCell ids.
+            if (RenderingDiagnostics.IsEnvCellId(id) && RenderingDiagnostics.ProbeIndoorUploadEnabled)
+            {
+                _pendingEnvCellRequests.Add(id);
+                Console.WriteLine($"[indoor-upload] requested cellId=0x{id:X8}");
+            }
         }
     }
 
@@ -172,7 +189,26 @@ public sealed class WbMeshAdapter : IDisposable, IWbMeshAdapter
         _graphicsDevice!.ProcessGLQueue();
         while (_meshManager!.StagedMeshData.TryDequeue(out var meshData))
         {
-            _meshManager.UploadMeshData(meshData);
+            // [indoor-upload] completed probe — check BEFORE upload so we
+            // see what WB actually produced (vertex counts, parts) before
+            // any post-upload mutation.
+            bool isPendingEnvCell = RenderingDiagnostics.ProbeIndoorUploadEnabled
+                && _pendingEnvCellRequests.Remove(meshData.ObjectId);
+
+            var renderData = _meshManager.UploadMeshData(meshData);
+
+            if (isPendingEnvCell)
+            {
+                int parts = meshData.SetupParts?.Count ?? 0;
+                bool hasGeom = meshData.EnvCellGeometry is not null;
+                int cellGeomVerts = meshData.EnvCellGeometry?.Vertices?.Length ?? 0;
+                bool uploadOk = renderData is not null;
+                Console.WriteLine(
+                    $"[indoor-upload] completed cellId=0x{meshData.ObjectId:X8} " +
+                    $"isSetup={meshData.IsSetup} parts={parts} " +
+                    $"hasEnvCellGeom={hasGeom} cellGeomVerts={cellGeomVerts} " +
+                    $"uploadOk={uploadOk}");
+            }
         }
     }