feat(admin): 添加后台显示设置功能

- 新增后台显示设置页面，允许自定义布局标题
- 在布局组件中动态显示自定义标题
- 在后端添加对应的 API 端点用于获取和保存显示配置
- 移除无用的 Demo.vue 组件文件

cwd-api/src/index.ts

@@ -49,6 +49,11 @@ const COMMENT_ADMIN_KEY_HASH_KEY = 'comment_admin_key_hash';
 const COMMENT_REQUIRE_REVIEW_KEY = 'comment_require_review';
 const COMMENT_BLOCKED_IPS_KEY = 'comment_blocked_ips';
 const COMMENT_BLOCKED_EMAILS_KEY = 'comment_blocked_emails';
+const ADMIN_DISPLAY_CONFIG_KEY = 'admin_display_config';
+
+type AdminDisplaySettings = {
+	layoutTitle: string;
+};
 
 async function loadCommentSettings(env: Bindings) {
 	await env.CWD_DB.prepare('CREATE TABLE IF NOT EXISTS Settings (key TEXT PRIMARY KEY, value TEXT NOT NULL)').run();
@@ -119,6 +124,43 @@ async function loadCommentSettings(env: Bindings) {
 	};
 }
 
+async function loadAdminDisplaySettings(env: Bindings): Promise<AdminDisplaySettings> {
+	await env.CWD_DB.prepare('CREATE TABLE IF NOT EXISTS Settings (key TEXT PRIMARY KEY, value TEXT NOT NULL)').run();
+	const row = await env.CWD_DB.prepare('SELECT value FROM Settings WHERE key = ?')
+		.bind(ADMIN_DISPLAY_CONFIG_KEY)
+		.first<{ value: string }>();
+
+	const defaults: AdminDisplaySettings = {
+		layoutTitle: 'CWD 评论系统',
+	};
+
+	if (!row || !row.value) {
+		return defaults;
+	}
+
+	try {
+		const parsed = JSON.parse(row.value) as Partial<AdminDisplaySettings>;
+		const result: AdminDisplaySettings = {
+			layoutTitle: typeof parsed.layoutTitle === 'string' && parsed.layoutTitle ? parsed.layoutTitle : defaults.layoutTitle,
+		};
+		return result;
+	} catch {
+		return defaults;
+	}
+}
+
+async function saveAdminDisplaySettings(env: Bindings, settings: Partial<AdminDisplaySettings>) {
+	await env.CWD_DB.prepare('CREATE TABLE IF NOT EXISTS Settings (key TEXT PRIMARY KEY, value TEXT NOT NULL)').run();
+
+	const current = await loadAdminDisplaySettings(env);
+	const next: AdminDisplaySettings = {
+		layoutTitle: settings.layoutTitle !== undefined ? settings.layoutTitle : current.layoutTitle,
+	};
+
+	const value = JSON.stringify(next);
+	await env.CWD_DB.prepare('REPLACE INTO Settings (key, value) VALUES (?, ?)').bind(ADMIN_DISPLAY_CONFIG_KEY, value).run();
+}
+
 async function saveCommentSettings(
 	env: Bindings,
 	settings: {
@@ -291,6 +333,30 @@ app.put('/admin/settings/telegram', updateTelegramSettings);
 app.post('/admin/settings/telegram/setup', setupTelegramWebhook);
 app.post('/admin/settings/telegram/test', testTelegramMessage);
 
+app.get('/admin/settings/admin-display', async (c) => {
+	try {
+		const settings = await loadAdminDisplaySettings(c.env);
+		return c.json(settings);
+	} catch (e: any) {
+		return c.json({ message: e.message || '加载显示配置失败' }, 500);
+	}
+});
+
+app.put('/admin/settings/admin-display', async (c) => {
+	try {
+		const body = await c.req.json();
+		const layoutTitle = typeof body.layoutTitle === 'string' ? body.layoutTitle : undefined;
+
+		await saveAdminDisplaySettings(c.env, {
+			layoutTitle,
+		});
+
+		return c.json({ message: '保存成功' });
+	} catch (e: any) {
+		return c.json({ message: e.message || '保存失败' }, 500);
+	}
+});
+
 app.get('/admin/settings/comments', async (c) => {
 	try {
 		const settings = await loadCommentSettings(c.env);