feat: 添加主题根据系统切换功能

feat: #387

src/i18n/lang/en-US/settings.ts

@@ -15,6 +15,8 @@ export default {
   basic: {
     themeMode: 'Theme Mode',
     themeModeDesc: 'Switch between light/dark theme',
+    autoTheme: 'Follow System',
+    manualTheme: 'Manual Switch',
     language: 'Language Settings',
     languageDesc: 'Change display language',
     font: 'Font Settings',

src/i18n/lang/zh-CN/settings.ts

@@ -15,6 +15,8 @@ export default {
   basic: {
     themeMode: '主题模式',
     themeModeDesc: '切换日间/夜间主题',
+    autoTheme: '跟随系统',
+    manualTheme: '手动切换',
     language: '语言设置',
     languageDesc: '切换显示语言',
     font: '字体设置',

src/i18n/lang/zh-Hant/settings.ts

@@ -15,6 +15,8 @@ export default {
   basic: {
     themeMode: '主題模式',
     themeModeDesc: '切換日間/夜間主題',
+    autoTheme: '跟隨系統',
+    manualTheme: '手動切換',
     language: '語言設定',
     languageDesc: '切換顯示語言',
     font: '字體設定',