feat: 添加IPv6地址获取功能，优化Cloudflare DNS记录更新逻辑，更新版本号并添加README

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@kevisual/ddns-agent",
-  "version": "1.0.3",
+  "version": "1.0.4",
   "description": "",
   "main": "index.js",
   "type": "module",
@@ -14,7 +14,7 @@
     ]
   },
   "scripts": {
-    "pub": "ev deploy . -k ddns-agent -v 1.0.3 -u",
+    "pub": "ev deploy . -k ddns-agent -v 1.0.4 -u",
     "packup": "ev pack -p",
     "pm2": "pm2 start agent/main.ts --interpreter bun --name ddns-agent"
   },