chore(O-T7): code-review housekeeping after WB extraction

Five small post-cleanup items from T7 code review:

I1: Removed dead `datDir` parameter from WbMeshAdapter ctor (parameter
    was unused after _wbDats removal; ArgumentNullException.ThrowIfNull
    was misleading). Updated call sites in GameWindow.cs and
    WbMeshAdapterTests.cs.

I2: Updated stale GameWindow.cs comment that still described
    WbMeshAdapter as opening its own dat handles. Now reflects Phase O
    state: shared DatCollection via DatCollectionAdapter.

I3: Documented thread-safety contract on RenderStateCache (render-thread
    only — required for the mutable-static GL sentinel pattern).

M1: Added comment on IDatReaderWriter's write-path methods noting they
    are preserved for verbatim compatibility but unused in acdream.

M3: Added comment on Chorizite.Core PackageReference in Core.csproj
    explaining the previously-transitive dependency.

Also excluded SplitFormulaDivergenceTest.cs from the test build via
<Compile Remove>: this N.5b one-time data-collection test referenced
WorldBuilder.Shared types directly; after Phase O-T7 dropped that
project reference it no longer compiles. The sweep data it produced
already informed the N.5b Path-C decision and the file is retained
in the tree for historical reference.

Build green; tests green (1146 + 8 pre-existing failures baseline
maintained).

Spec: docs/superpowers/specs/2026-05-21-phase-o-dat-path-unification-design.md

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

src/AcDream.App/Rendering/GameWindow.cs

@@ -1651,11 +1651,13 @@ public sealed class GameWindow : IDisposable
 
         // Phase N.4+N.5 — WB rendering pipeline foundation. The modern path is
         // mandatory as of N.5 ship amendment: WbMeshAdapter + WbDrawDispatcher
-        // always construct. WbMeshAdapter owns ObjectMeshManager and opens its
-        // own file handles for the dat files (independent of our DatCollection).
+        // always construct.
+        // Phase O (2026-05-21): WbMeshAdapter now consumes our DatCollection
+        // directly via DatCollectionAdapter. No second dat reader; index cache
+        // is shared with the rest of the client.
         {
             var wbLogger = Microsoft.Extensions.Logging.Abstractions.NullLogger<AcDream.App.Rendering.Wb.WbMeshAdapter>.Instance;
-            _wbMeshAdapter = new AcDream.App.Rendering.Wb.WbMeshAdapter(_gl, _datDir, _dats, wbLogger);
+            _wbMeshAdapter = new AcDream.App.Rendering.Wb.WbMeshAdapter(_gl, _dats, wbLogger);
             Console.WriteLine("[N.4+N.5] WB foundation + modern path active — routing all content through ObjectMeshManager.");
         }
 

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

@@ -71,6 +71,8 @@ public interface IDatReaderWriter : IDisposable {
     /// </summary>
     int LanguageIteration { get; }
 
+    // Write-path methods — preserved from WB's interface for verbatim
+    // compatibility but not exercised by ObjectMeshManager in acdream.
     /// <summary>Attempts to save a database object to the appropriate DAT.</summary>
     bool TrySave<T>(T obj, int iteration = 0) where T : IDBObj;
 

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

@@ -12,6 +12,12 @@ namespace AcDream.App.Rendering.Wb;
 ///   <c>CurrentIBO</c>    — OpenGL name of the currently bound index buffer object.
 /// Sentinel value 0 means "no valid binding cached."
 /// </summary>
+/// <remarks>
+/// All accesses must occur on the render thread. GL state binding is
+/// not thread-safe; these sentinels are written immediately after the
+/// corresponding glBind* call and read by the next dispatch on the
+/// same thread.
+/// </remarks>
 public static class RenderStateCache
 {
     public static uint CurrentAtlas = 0;

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

@@ -43,17 +43,14 @@ public sealed class WbMeshAdapter : IDisposable, IWbMeshAdapter
     /// </summary>
     /// <param name="gl">Active Silk.NET GL context. Must be bound to the current
     /// thread (construction runs GL queries; call from OnLoad).</param>
-    /// <param name="datDir">Path to the dat directory. Retained for API compatibility;
-    /// DatCollectionAdapter routes all DAT I/O through our shared DatCollection.</param>
     /// <param name="dats">acdream's DatCollection, used to populate the surface
     /// metadata side-table via <c>GfxObjMesh.Build</c>. Shares file handles with
     /// the rest of the client; read-only access from the render thread.</param>
     /// <param name="logger">Logger for the adapter; ObjectMeshManager uses
     /// NullLogger internally.</param>
-    public WbMeshAdapter(GL gl, string datDir, DatCollection dats, ILogger<WbMeshAdapter> logger)
+    public WbMeshAdapter(GL gl, DatCollection dats, ILogger<WbMeshAdapter> logger)
     {
         ArgumentNullException.ThrowIfNull(gl);
-        ArgumentNullException.ThrowIfNull(datDir);
         ArgumentNullException.ThrowIfNull(dats);
         ArgumentNullException.ThrowIfNull(logger);
 

src/AcDream.Core/AcDream.Core.csproj

@@ -8,6 +8,10 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="BCnEncoder.Net" Version="2.2.1" />
+    <!-- Phase O (2026-05-21): Chorizite.Core was previously transitive
+         via the WorldBuilder.Shared project reference. After T7 dropped
+         that, Core's TextureHelpers needs an explicit reference for
+         Chorizite.Core.Render.Enums.TextureFormat. -->
     <PackageReference Include="Chorizite.Core" Version="0.0.18" />
     <PackageReference Include="Chorizite.DatReaderWriter" Version="2.1.7" />
     <PackageReference Include="Serilog" Version="4.0.2" />