fix: show total lessons instead of next milestone in progress text

The progress text was showing "0 of 1" (next milestone) which was confusing.
Now shows "0 of 101" (total lessons) while milestone dots show the milestone progression.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

src/app.js

@@ -320,10 +320,10 @@ function updateProgressDisplay() {
 	// Update progress bar (now shows progress to next milestone)
 	elements.progressFill.style.width = `${stats.progressToNext}%`;
 
-	// Update progress text
+	// Update progress text - show completed of total lessons
 	elements.progressText.textContent = t("progressTextMilestone", {
 		completed: stats.totalCompleted,
-		next: stats.nextMilestone
+		total: stats.totalLessons
 	});
 
 	// Update milestone indicators

src/i18n.js

@@ -39,7 +39,7 @@ const translations = {
 		language: "Language",
 		progress: "Progress",
 		progressText: "{percent}% Complete ({completed}/{total})",
-		progressTextMilestone: "{completed} of {next}",
+		progressTextMilestone: "{completed} of {total}",
 		lessons: "Lessons",
 		settings: "Settings",
 		showHints: "Show Hints",
@@ -261,7 +261,7 @@ const translations = {
 		language: "Sprache",
 		progress: "Fortschritt",
 		progressText: "{percent}% abgeschlossen ({completed}/{total})",
-		progressTextMilestone: "{completed} von {next}",
+		progressTextMilestone: "{completed} von {total}",
 		lessons: "Lektionen",
 		settings: "Einstellungen",
 		showHints: "Hinweise anzeigen",
@@ -483,7 +483,7 @@ const translations = {
 		language: "Język",
 		progress: "Postęp",
 		progressText: "{percent}% ukończone ({completed}/{total})",
-		progressTextMilestone: "{completed} z {next}",
+		progressTextMilestone: "{completed} z {total}",
 		lessons: "Lekcje",
 		settings: "Ustawienia",
 		showHints: "Pokaż podpowiedzi",
@@ -704,7 +704,7 @@ const translations = {
 		language: "Idioma",
 		progress: "Progreso",
 		progressText: "{percent}% completado ({completed}/{total})",
-		progressTextMilestone: "{completed} de {next}",
+		progressTextMilestone: "{completed} de {total}",
 		lessons: "Lecciones",
 		settings: "Configuración",
 		showHints: "Mostrar pistas",
@@ -927,7 +927,7 @@ const translations = {
 		language: "اللغة",
 		progress: "التقدم",
 		progressText: "{percent}% مكتمل ({completed}/{total})",
-		progressTextMilestone: "{completed} من {next}",
+		progressTextMilestone: "{completed} من {total}",
 		lessons: "الدروس",
 		settings: "الإعدادات",
 		showHints: "إظهار التلميحات",
@@ -1145,7 +1145,7 @@ const translations = {
 		language: "Мова",
 		progress: "Прогрес",
 		progressText: "{percent}% завершено ({completed}/{total})",
-		progressTextMilestone: "{completed} з {next}",
+		progressTextMilestone: "{completed} з {total}",
 		lessons: "Уроки",
 		settings: "Налаштування",
 		showHints: "Показувати підказки",