Change black empty tile to grass and make it destructable

src/rendering/DungeonRenderer.ts

@@ -110,6 +110,15 @@ export class DungeonRenderer {
     // Update Tiles
     this.layer.forEachTile(tile => {
       const i = idx(this.world, tile.x, tile.y);
+      const worldTile = this.world.tiles[i];
+      
+      // Sync visual tile with logical tile (e.g. if grass was destroyed)
+      if (tile.index !== worldTile) {
+        // We can safely update the index property for basic tile switching
+        // If we needed to change collision properties, we'd use putTileAt
+        tile.index = worldTile;
+      }
+
       const isSeen = seen[i] === 1;
       const isVis = visible[i] === 1;