refactor(pipeline): MP1a - MeshExtractor extracted to AcDream.Content (verbatim move)

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

@@ -1,3 +1,4 @@
+using AcDream.Content;
 using DatReaderWriter;
 using DatReaderWriter.Enums;
 using DatReaderWriter.Lib.IO;

src/AcDream.Content/EdgeLineBuilder.cs

@@ -1,7 +1,11 @@
 using System.Numerics;
 using DatReaderWriter.Types;
 
-namespace AcDream.App.Rendering.Wb {
+// MP1a (2026-07-05, Task 4): moved to AcDream.Content, namespace only —
+// consumed by MeshExtractor.PrepareCellStructEdgeLineData, which must be
+// GL-free.
+
+namespace AcDream.Content {
     public static class EdgeLineBuilder {
         public static List<Vector3> BuildEdgeLines(CellStruct cellStruct) {
             var edgeMap = new Dictionary<EdgeKey, List<Edge>>();

src/AcDream.Content/IDatReaderWriter.cs

@@ -9,8 +9,13 @@ using System.Diagnostics.CodeAnalysis;
 // WorldBuilder.Shared project reference can be dropped.
 // The only consumer of IDatReaderWriter in acdream is DatCollectionAdapter +
 // ObjectMeshManager, both already in this namespace.
+//
+// MP1a (2026-07-05, Task 4): moved to AcDream.Content, namespace only —
+// MeshExtractor's constructor takes IDatReaderWriter and must be GL-free.
+// DatCollectionAdapter (the concrete DatCollection-backed implementation)
+// stays in AcDream.App; it now implements this Content-namespaced interface.
 
-namespace AcDream.App.Rendering.Wb;
+namespace AcDream.Content;
 
 /// <summary>
 /// Interface for the dat reader/writer