feat(analytics): 添加访问统计功能

实现页面访问统计功能，包括：
1. 前端组件挂载时上报访问数据
2. 后端接口记录访问信息并存储
3. 管理后台新增访问统计视图
4. 相关API文档和设计说明更新

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

@@ -0,0 +1,78 @@
+import type { Context } from 'hono';
+import type { Bindings } from '../../bindings';
+
+type VisitOverview = {
+	totalPv: number;
+	totalPages: number;
+};
+
+type VisitPageItem = {
+	postSlug: string;
+	postTitle: string | null;
+	postUrl: string | null;
+	pv: number;
+	lastVisitAt: string | null;
+};
+
+export const getVisitOverview = async (
+	c: Context<{ Bindings: Bindings }>
+) => {
+	try {
+		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 TEXT, created_at TEXT NOT NULL, updated_at TEXT NOT NULL)'
+		).run();
+
+		const row = await c.env.CWD_DB.prepare(
+			'SELECT COUNT(*) as totalPages, COALESCE(SUM(pv), 0) as totalPv FROM page_stats'
+		).first<{
+			totalPages: number | null;
+			totalPv: number | null;
+		}>();
+
+		const data: VisitOverview = {
+			totalPv: row?.totalPv || 0,
+			totalPages: row?.totalPages || 0
+		};
+
+		return c.json(data);
+	} catch (e: any) {
+		return c.json(
+			{ message: e.message || '获取访问统计概览失败' },
+			500
+		);
+	}
+};
+
+export const getVisitPages = async (c: Context<{ Bindings: Bindings }>) => {
+	try {
+		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 TEXT, created_at TEXT NOT NULL, updated_at TEXT NOT NULL)'
+		).run();
+
+		const { results } = await c.env.CWD_DB.prepare(
+			'SELECT post_slug, post_title, post_url, pv, last_visit_at FROM page_stats ORDER BY pv DESC, last_visit_at DESC'
+		).all<{
+			post_slug: string;
+			post_title: string | null;
+			post_url: string | null;
+			pv: number;
+			last_visit_at: string | null;
+		}>();
+
+		const items: VisitPageItem[] = results.map((row) => ({
+			postSlug: row.post_slug,
+			postTitle: row.post_title,
+			postUrl: row.post_url,
+			pv: row.pv || 0,
+			lastVisitAt: row.last_visit_at
+		}));
+
+		return c.json({ items });
+	} catch (e: any) {
+		return c.json(
+			{ message: e.message || '获取页面访问统计失败' },
+			500
+		);
+	}
+};
+