feat(actions): config-driven action whitelist registry

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

lib/actions/registry.js

@@ -0,0 +1,29 @@
+import { readFileSync } from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const DEFAULT = path.join(path.dirname(fileURLToPath(import.meta.url)), '../../config/actions.json');
+const ID_RE = /^[a-z0-9-]+$/;
+const KINDS = new Set(['service_restart', 'guest_power']);
+const OPS = new Set(['start', 'stop', 'shutdown', 'reboot']);
+const TIERS = new Set(['safe', 'risky']);
+
+// Loads + validates the action whitelist. `raw` overrides file read (tests).
+export function loadActions(file = DEFAULT, raw) {
+  const cfg = raw || JSON.parse(readFileSync(file, 'utf8'));
+  const hosts = cfg.hosts || {};
+  const byId = new Map();
+  for (const a of (cfg.actions || [])) {
+    if (!ID_RE.test(a.id || '')) throw new Error(`invalid action id: ${a.id}`);
+    if (!KINDS.has(a.kind)) throw new Error(`unknown kind: ${a.kind}`);
+    if (!TIERS.has(a.tier)) throw new Error(`invalid tier: ${a.tier}`);
+    if (a.kind === 'guest_power' && !OPS.has(a.op)) throw new Error(`invalid op: ${a.op}`);
+    if (byId.has(a.id)) throw new Error(`duplicate action id: ${a.id}`);
+    byId.set(a.id, a);
+  }
+  return {
+    list: () => [...byId.values()],
+    get: (id) => byId.get(id),
+    hostIp: (h) => hosts[h]
+  };
+}