introduce bitloops

src/main/java/puzzle/Export.java

@@ -38,7 +38,7 @@ public record Export() {
       }
    }
    
-   public record Clued(Clues mask) {
+   public record Clued(@Delegate Clues mask) {
       
       String gridToString() {
          var sb = new StringBuilder();
@@ -190,7 +190,7 @@ public record Export() {
          var g       = filled().grid();
          var placed  = new ArrayList<Placed>();
          var clueMap = filled().clueMap();
-         g.grid().forEachSlot((int key, long lo, long hi) -> {
+         mask.forEachSlot((int key, long lo, long hi) -> {
             var word = clueMap[key];
             if (word != 0L) {
                placed.add(extractPlacedFromSlot(Slot.from(key, lo, hi), word));