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/public/trackVisit.ts

@@ -0,0 +1,69 @@
+import type { Context } from 'hono';
+import type { Bindings } from '../../bindings';
+
+type TrackVisitBody = {
+	postSlug?: string;
+	postTitle?: string;
+	postUrl?: string;
+};
+
+export const trackVisit = async (c: Context<{ Bindings: Bindings }>) => {
+	try {
+		const body = (await c.req.json().catch(() => ({}))) as TrackVisitBody;
+
+		const rawPostSlug = typeof body.postSlug === 'string' ? body.postSlug.trim() : '';
+		const rawPostTitle = typeof body.postTitle === 'string' ? body.postTitle.trim() : '';
+		const rawPostUrl = typeof body.postUrl === 'string' ? body.postUrl.trim() : '';
+
+		if (!rawPostSlug) {
+			return c.json({ message: 'postSlug is required' }, 400);
+		}
+
+		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 now = new Date().toISOString();
+
+		const existing = await c.env.CWD_DB.prepare(
+			'SELECT id, pv FROM page_stats WHERE post_slug = ?'
+		)
+			.bind(rawPostSlug)
+			.first<{ id: number; pv: number }>();
+
+		if (!existing) {
+			await c.env.CWD_DB.prepare(
+				'INSERT INTO page_stats (post_slug, post_title, post_url, pv, last_visit_at, created_at, updated_at) VALUES (?, ?, ?, ?, ?, ?, ?)'
+			)
+				.bind(
+					rawPostSlug,
+					rawPostTitle || null,
+					rawPostUrl || null,
+					1,
+					now,
+					now,
+					now
+				)
+				.run();
+		} else {
+			const newPv = (existing.pv || 0) + 1;
+			await c.env.CWD_DB.prepare(
+				'UPDATE page_stats SET post_title = ?, post_url = ?, pv = ?, last_visit_at = ?, updated_at = ? WHERE id = ?'
+			)
+				.bind(
+					rawPostTitle || null,
+					rawPostUrl || null,
+					newPv,
+					now,
+					now,
+					existing.id
+				)
+				.run();
+		}
+
+		return c.json({ success: true });
+	} catch (e: any) {
+		return c.json({ message: e.message || '记录访问数据失败' }, 500);
+	}
+};
+