fix(ludo): prevent pawns on safe squares from being sent home

Two bugs caused pawns to teleport back to the yard without capture:

1. Triple-six penalty blindly sent the last-moved piece to pos=-1
   regardless of whether it was resting on a safe square. Now the
   penalty only applies if the piece is NOT on a safe square.

2. captureAt() checked if the DESTINATION was safe but didn't guard
   against the victim's own position being safe. Added a per-piece
   safety check so a pawn sitting on any safe square (star squares,
   colored start squares) can never be captured under any circumstance.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

public/js/modules/ludo/logic/rules.js

@@ -219,8 +219,14 @@ export function applyMove(game, playerIdx, move) {
     game.extraTurn = true;
     player.consecutiveSixes = (player.consecutiveSixes || 0) + 1;
     if (player.consecutiveSixes >= 3) {
-      piece.pos = -1;
-      piece.finished = false;
+      // Triple-six penalty: send piece home ONLY if it's NOT resting on a safe square
+      const penaltyGlobal = piece.pos >= 0 && piece.pos <= HOME_ENTRY_POS
+        ? (piece.pos + START_POSITIONS[playerIdx]) % SHARED_PATH_LENGTH
+        : -1;
+      if (penaltyGlobal === -1 || !SAFE_SQUARES.includes(penaltyGlobal)) {
+        piece.pos = -1;
+        piece.finished = false;
+      }
       player.consecutiveSixes = 0;
       game.extraTurn = false;
     }
@@ -266,6 +272,8 @@ function captureAt(game, playerIdx, globalPos) {
       if (piece.pos === -1 || piece.finished) continue;
       if (piece.pos > HOME_ENTRY_POS) continue;
       const theirGlobal = (piece.pos + START_POSITIONS[i]) % SHARED_PATH_LENGTH;
+      // Double-check: never capture a piece sitting on ANY safe square
+      if (SAFE_SQUARES.includes(theirGlobal)) continue;
       if (theirGlobal === globalPos) {
         piece.pos = -1;
         if (!captured.includes(i)) captured.push(i);