fix: add dieUsed property to bot move sequences

getAllMovesForDice was returning moves without dieUsed, causing
"(undefined)" in bot move log messages.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

public/js/backgammon-constants.js

@@ -206,8 +206,9 @@ var BackgammonConstants = (function() {
                     nextDice.splice(i, 1);
 
                     for (var m = 0; m < moves.length; m++) {
-                        var result = applyMove(curBoard, curBar, curBorneOff, player, moves[m]);
-                        var newSeq = sequence.concat([moves[m]]);
+                        var moveWithDie = { from: moves[m].from, to: moves[m].to, hit: moves[m].hit, dieUsed: die };
+                        var result = applyMove(curBoard, curBar, curBorneOff, player, moveWithDie);
+                        var newSeq = sequence.concat([moveWithDie]);
                         dfs(result.board, result.bar, result.borneOff, nextDice, newSeq);
                     }
                 }