feat(admin): 添加域名列表获取功能用于筛选

新增获取域名列表的API端点，用于统一管理评论和访问统计中的域名筛选功能。修改了前端多个视图的域名获取逻辑，从原来的分散获取改为统一调用新接口，提高代码复用性和维护性。

docs: 添加反馈页面并更新侧边栏

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

@@ -0,0 +1,74 @@
+import type { Context } from 'hono';
+import type { Bindings } from '../../bindings';
+
+function extractDomain(source: string | null | undefined): string | null {
+	if (!source) {
+		return null;
+	}
+	const value = source.trim();
+	if (!value) {
+		return null;
+	}
+	if (!/^https?:\/\//i.test(value)) {
+		return null;
+	}
+	try {
+		const url = new URL(value);
+		return url.hostname.toLowerCase();
+	} catch {
+		return null;
+	}
+}
+
+export const getDomains = async (c: Context<{ Bindings: Bindings }>) => {
+	try {
+		const domains = new Set<string>();
+
+		const { results: commentRows } = await c.env.CWD_DB.prepare(
+			'SELECT post_slug, url FROM Comment'
+		).all<{
+			post_slug: string;
+			url: string | null;
+		}>();
+
+		for (const row of commentRows) {
+			const domain =
+				extractDomain(row.post_slug) || extractDomain(row.url);
+			if (domain) {
+				domains.add(domain);
+			}
+		}
+
+		await c.env.CWD_DB.prepare(
+			'CREATE TABLE IF NOT EXISTS page_stats (id INTEGER PRIMARY KEY AUTOINCREMENT, post_slug TEXT UNIQUE NOT NULL, post_title TEXT, post_url TEXT, pv INTEGER NOT NULL DEFAULT 0, last_visit_at INTEGER, created_at INTEGER NOT NULL, updated_at INTEGER NOT NULL)'
+		).run();
+
+		const { results: pageRows } = await c.env.CWD_DB.prepare(
+			'SELECT post_slug, post_url FROM page_stats'
+		).all<{
+			post_slug: string;
+			post_url: string | null;
+		}>();
+
+		for (const row of pageRows) {
+			const domain =
+				extractDomain(row.post_url) || extractDomain(row.post_slug);
+			if (domain) {
+				domains.add(domain);
+			}
+		}
+
+		const list = Array.from(domains);
+		list.sort();
+
+		return c.json({
+			domains: list
+		});
+	} catch (e: any) {
+		return c.json(
+			{ message: e.message || '获取域名列表失败' },
+			500
+		);
+	}
+};
+