fix(i18n): restore pre-existing AppearanceSettings translations

Task 7 inadvertently overwrote 18 carefully-tuned translations across 7 languages
(ar/de/es/fr/ja/ko/pt) with the plan author's slightly different wording while
adding the new themeColor / zoomLevel / resetToDefaults keys. The new additions
remain intact; only the pre-existing keys are reverted to the project's original
translations (e.g. de "Designmodus" instead of "Design-Modus", ja
"システム追従" instead of "システムに従う"). Affects: sectionDescription,
themeMode, placeholder, system, currentTheme.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/i18n/messages/ar.json

@@ -100,13 +100,13 @@
   },
   "AppearanceSettings": {
     "sectionTitle": "مظهر السمة",
-    "sectionDescription": "اختر فاتح أو داكن أو اتباع النظام. يتم حفظ الإعدادات تلقائياً.",
+    "sectionDescription": "اختر الفاتح أو الداكن أو اتباع النظام. يتم حفظ الإعدادات تلقائيًا.",
     "themeMode": "وضع السمة",
     "placeholder": "اختر وضع السمة",
     "system": "اتباع النظام",
     "light": "فاتح",
     "dark": "داكن",
-    "currentTheme": "السمة الحالية: {theme}",
+    "currentTheme": "السمة الفعالة الحالية: {theme}",
     "resolvedTheme": {
       "light": "فاتح",
       "dark": "داكن",

src/i18n/messages/de.json

@@ -100,10 +100,10 @@
   },
   "AppearanceSettings": {
     "sectionTitle": "Design-Erscheinungsbild",
-    "sectionDescription": "Wähle Hell, Dunkel oder System folgen. Einstellungen werden automatisch gespeichert.",
-    "themeMode": "Design-Modus",
-    "placeholder": "Design-Modus wählen",
-    "system": "System folgen",
+    "sectionDescription": "Wähle hell, dunkel oder Systemvorgabe. Einstellungen werden automatisch gespeichert.",
+    "themeMode": "Designmodus",
+    "placeholder": "Designmodus auswählen",
+    "system": "Systemvorgabe",
     "light": "Hell",
     "dark": "Dunkel",
     "currentTheme": "Aktuell wirksames Design: {theme}",

src/i18n/messages/es.json

@@ -101,12 +101,12 @@
   "AppearanceSettings": {
     "sectionTitle": "Apariencia del tema",
     "sectionDescription": "Elige claro, oscuro o seguir el sistema. La configuración se guarda automáticamente.",
-    "themeMode": "Modo del tema",
-    "placeholder": "Selecciona el modo del tema",
+    "themeMode": "Modo de tema",
+    "placeholder": "Selecciona el modo de tema",
     "system": "Seguir el sistema",
     "light": "Claro",
     "dark": "Oscuro",
-    "currentTheme": "Tema actual: {theme}",
+    "currentTheme": "Tema efectivo actual: {theme}",
     "resolvedTheme": {
       "light": "Claro",
       "dark": "Oscuro",

src/i18n/messages/fr.json

@@ -102,11 +102,11 @@
     "sectionTitle": "Apparence du thème",
     "sectionDescription": "Choisissez clair, sombre ou suivre le système. Les paramètres sont enregistrés automatiquement.",
     "themeMode": "Mode du thème",
-    "placeholder": "Sélectionnez le mode du thème",
+    "placeholder": "Sélectionner le mode du thème",
     "system": "Suivre le système",
     "light": "Clair",
     "dark": "Sombre",
-    "currentTheme": "Thème actuellement appliqué : {theme}",
+    "currentTheme": "Thème effectif actuel : {theme}",
     "resolvedTheme": {
       "light": "Clair",
       "dark": "Sombre",

src/i18n/messages/ja.json

@@ -100,13 +100,13 @@
   },
   "AppearanceSettings": {
     "sectionTitle": "テーマ外観",
-    "sectionDescription": "ライト、ダーク、またはシステムに従うを選択します。設定は自動的に保存されます。",
+    "sectionDescription": "ライト、ダーク、またはシステム追従を選択できます。設定は自動保存されます。",
     "themeMode": "テーマモード",
     "placeholder": "テーマモードを選択",
     "system": "システムに従う",
     "light": "ライト",
     "dark": "ダーク",
-    "currentTheme": "現在有効なテーマ：{theme}",
+    "currentTheme": "現在の有効テーマ: {theme}",
     "resolvedTheme": {
       "light": "ライト",
       "dark": "ダーク",

src/i18n/messages/ko.json

@@ -100,10 +100,10 @@
   },
   "AppearanceSettings": {
     "sectionTitle": "테마 모양",
-    "sectionDescription": "라이트, 다크 또는 시스템 따르기를 선택하세요. 설정은 자동으로 저장됩니다.",
+    "sectionDescription": "라이트, 다크 또는 시스템 설정을 선택할 수 있습니다. 설정은 자동으로 저장됩니다.",
     "themeMode": "테마 모드",
     "placeholder": "테마 모드 선택",
-    "system": "시스템 따르기",
+    "system": "시스템 설정 따름",
     "light": "라이트",
     "dark": "다크",
     "currentTheme": "현재 적용된 테마: {theme}",

src/i18n/messages/pt.json

@@ -101,12 +101,12 @@
   "AppearanceSettings": {
     "sectionTitle": "Aparência do tema",
     "sectionDescription": "Escolha claro, escuro ou seguir o sistema. As configurações são salvas automaticamente.",
-    "themeMode": "Modo do tema",
-    "placeholder": "Selecione o modo do tema",
+    "themeMode": "Modo de tema",
+    "placeholder": "Selecionar modo de tema",
     "system": "Seguir o sistema",
     "light": "Claro",
     "dark": "Escuro",
-    "currentTheme": "Tema atualmente em uso: {theme}",
+    "currentTheme": "Tema efetivo atual: {theme}",
     "resolvedTheme": {
       "light": "Claro",
       "dark": "Escuro",