feat: 添加自动迁移脚本并分离评论的slug和URL字段

- 新增自动数据库迁移脚本，在部署前检查并更新schema
- 将post_slug字段拆分为post_slug（仅路径）和post_url（完整URL）
- 更新前端widget以仅使用路径作为post_slug
- 修改部署脚本以在部署前自动运行迁移

cwd-api/src/api/public/postComment.ts

@@ -159,13 +159,14 @@ export const postComment = async (c: Context<{ Bindings: Bindings }>) => {
   try {
     const result = await c.env.CWD_DB.prepare(`
       INSERT INTO Comment (
-        created, post_slug, name, email, url, ip_address, 
+        created, post_slug, post_url, name, email, url, ip_address, 
         os, browser, device, ua, content_text, content_html, 
         parent_id, status
-      ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+      ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
     `).bind(
       Date.now(),
       post_slug,
+      post_url || null,
       name,
       email,
       url || null,