build: install telnet in runtime image

Dockerfile

@@ -16,7 +16,7 @@ ARG TARGETARCH
 # Node 从 NodeSource 装 20.x：bookworm 自带的 apt nodejs 是 18，Playwright 要求 >=20。
 RUN apt-get update && apt-get install -y --no-install-recommends \
       ca-certificates ripgrep curl wget vim git jq unzip \
-      dnsutils iputils-ping netcat-openbsd whois nmap \
+      dnsutils iputils-ping netcat-openbsd inetutils-telnet whois nmap \
     && curl -fsSL https://deb.nodesource.com/setup_20.x | bash - \
     && apt-get install -y --no-install-recommends nodejs \
     && rm -rf /var/lib/apt/lists/*