New Atlas + Texture Pipeline

World/Blocks/IBlock.cs

@@ -11,8 +11,8 @@ public interface IBlock
     // Reserved for future collision (not used in the baseline).
     bool IsSolid { get; }
 
-    // Atlas tile index for the given face.
-    int GetTextureIndex(BlockFace face);
+    // Atlas tile coordinate for the given face.
+    TileCoord GetTextureTile(BlockFace face);
 
     // Interaction hooks — capability present now, system built post-baseline.
     void OnInteract() { }