feedback7 G-TOOLS: listen on :: by default so one socket serves IPv6 and IPv4 (PR #291 by @LimitlessHPPK)

Ported only the dual-stack listen from PR #291 (the change accepted as #188). With HOST unset the server binds :: and, if that fails with EAFNOSUPPORT, EADDRNOTAVAIL or EINVAL, retries 0.0.0.0. An explicit HOST, including 0.0.0.0 and 127.0.0.1, is tried once. The boot banner and doctor list shareable IPv6 addresses in brackets, skip fe80::, and keep one URL per /64. An explicit IPv6 literal in the local URL is bracketed. The Windows service listing no longer drops those bracketed lines.

Not ported: /dev/grant, the settings-default migration, and the firewall scripts. The Docker image stays on 0.0.0.0; the alpine fallback was not booted.

Tests: node --test test/ipv6-bind.test.js test/doctor.test.js test/ci.test.js — 20 pass, 0 fail (8 bind, 4 doctor, 8 ci).

docs/DEPLOY.md

@@ -106,7 +106,7 @@ powershell -ExecutionPolicy Bypass -File scripts\install-service-windows.ps1
 winget install NSSM.NSSM            # 或从 https://nssm.cc 下载
 nssm install StrongholdProtocol "C:\Program Files\nodejs\node.exe" server\index.js
 nssm set StrongholdProtocol AppDirectory C:\Stronghold-Protocol
-nssm set StrongholdProtocol AppEnvironmentExtra PORT=3000 HOST=0.0.0.0
+nssm set StrongholdProtocol AppEnvironmentExtra PORT=3000 HOST=::
 nssm set StrongholdProtocol AppStdout C:\Stronghold-Protocol\logs\server.log
 nssm set StrongholdProtocol AppStderr C:\Stronghold-Protocol\logs\server.log
 nssm start StrongholdProtocol
@@ -266,7 +266,7 @@ services:
   [Service]
   WorkingDirectory=/opt/Stronghold-Protocol
   ExecStart=/usr/bin/node server/index.js
-  Environment=PORT=3000 HOST=0.0.0.0
+  Environment=PORT=3000 HOST=::
   Restart=always
   RestartSec=5
   User=stronghold