feat(actions): configurable SSH user + insecure-TLS for PVE; real action whitelist + Z wrapper

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/actions/channels/ssh.js

@@ -7,7 +7,7 @@ const ID_RE = /^[a-z0-9-]+$/;
 // its OWN whitelist. We pass ONLY the id as a single argv element — no shell.
 export function restartService({ ip, actionId }, {
   keyPath = process.env.ACTIONS_SSH_KEY,
-  user = 'voidact',
+  user = process.env.ACTIONS_SSH_USER || 'voidact',
   spawnImpl = nodeSpawn
 } = {}) {
   if (!ID_RE.test(actionId || '')) return Promise.reject(new Error(`invalid action id: ${actionId}`));