feat(admin): 添加后台域名可见性管理功能

在后台设置页面新增域名管理选项卡，允许管理员配置后台下拉框中显示的域名列表。通过拖拽或点击按钮可以移动域名，实现灵活的可视域名控制。当配置了可见域名时，LayoutView 将只显示指定的域名，否则显示全部域名。

cwd-api/src/api/admin/featureSettings.ts

@@ -30,10 +30,15 @@ export const updateFeatureSettings = async (c: Context<{ Bindings: Bindings }>)
 		const commentPlaceholder =
 			rawCommentPlaceholder !== undefined ? rawCommentPlaceholder.trim() : undefined;
 
+		const visibleDomains = Array.isArray(body.visibleDomains)
+			? (body.visibleDomains as string[])
+			: undefined;
+
 		await saveFeatureSettings(c.env, {
 			enableCommentLike,
 			enableArticleLike,
-			commentPlaceholder
+			commentPlaceholder,
+			visibleDomains
 		});
 
 		return c.json({ message: '保存成功！' });