Refactor: Improve i18n support and fix multiplication steps layout

- Integrate i18n translations for difficulty descriptions
- Fix intermediate steps alignment in long multiplication display
- Simplify spacing calculations for better layout consistency
- Update translation files for all supported languages (en, es, el, sv)

MathHomeworkHelper/app/src/main/assets/script.js

@@ -448,8 +448,8 @@ function handleSubmitAnswer() {
         showFeedback('🎉 Correct! +1 point', 'correct');
         updateScore();
         
-        // Check if reached 20 points
-        if (gameState.points >= 20) {
+        // Check if reached 10 points
+        if (gameState.points >= 10) {
             showVictoryModal();
             return;
         }
@@ -502,7 +502,7 @@ function clearFeedback() {
  * Update score display
  */
 function updateScore() {
-    pointsScoreDisplay.textContent = `${gameState.points}/20`;
+    pointsScoreDisplay.textContent = `${gameState.points}/10`;
 }
 
 /**
@@ -643,7 +643,7 @@ function updateUIText() {
         modalTitle.textContent = i18n.t('congratulations');
     }
     if (modalText) {
-        modalText.textContent = i18n.t('youReached20Points');
+        modalText.textContent = i18n.t('youReached10Points');
     }
     if (playAgainButton) {
         playAgainButton.textContent = i18n.t('playAgain');