feat: rename CORS_ALLOW_ORIGIN to ASTRBOT_CORS_ALLOW_ORIGIN and add it to .env.example

.env.example

@@ -80,6 +80,12 @@ ASTRBOT_SYSTEMD=1
 # 默认 Default: True
 ASTRBOT_DASHBOARD_ENABLE=True
 
+# 允许跨域请求的来源域名（多个用逗号分隔，允许所有则用 *）
+# Allowed CORS origins for WebUI dashboard (comma-separated, or * for all)
+# 示例 Example: https://dash.astrbot.men
+# 默认 Default: *
+# ASTRBOT_CORS_ALLOW_ORIGIN="*"
+
 # ------------------------------------------
 # 国际化配置 / Internationalization Configuration
 # ------------------------------------------