feat(streaming): load full column bedrock->surface to fix terrain holes

Core/Configuration.cs

@@ -5,17 +5,6 @@ using OpenTK.Mathematics;
 public sealed class Configuration
 {
     public int RenderDistanceHorizontal { get; set; } = 8;
-    // Player-slab half-height in chunks. NOTE: repurposed by the visibility
-    // rework — this is no longer a global vertical load-box. It is how many
-    // chunks load above and below the player's chunk across the whole
-    // horizontal region, so caves at the player's depth render to the full
-    // horizontal distance.
-    public int RenderDistanceVertical { get; set; } = 2;
-
-    // Chunks loaded below the lowest surface chunk of each column. Gives the
-    // surface chunk a solid neighbor below (so its buried bottom faces cull)
-    // and covers cave mouths just under the surface.
-    public int SurfaceShellSkirtBelow { get; set; } = 1;
 
     // Distance fog begins at this fraction of the fog-end distance (fog end is
     // derived from RenderDistanceHorizontal). 0.7 → fog starts at 70% of the edge.