Desktop, Mobile: Automatically detect and use operating system theme by default

packages/lib/models/Setting.ts

@@ -113,6 +113,10 @@ const defaultMigrations: DefaultMigration[] = [
 		name: 'style.editor.contentMaxWidth',
 		previousDefault: 600,
 	},
+	{
+		name: 'themeAutoDetect',
+		previousDefault: false,
+	},
 ];
 
 // "UserSettingMigration" are used to migrate existing user setting to a new setting. With a way

packages/lib/models/settings/builtInMetadata.ts

@@ -543,7 +543,7 @@ const builtInMetadata = (Setting: typeof SettingType) => {
 		},
 
 		themeAutoDetect: {
-			value: false,
+			value: true,
 			type: SettingItemType.Bool,
 			section: 'appearance',
 			appTypes: [AppType.Mobile, AppType.Desktop],