feat: worker in-process de refresh périodique (croner)

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

server/jobs/worker.ts

@@ -0,0 +1,24 @@
+// server/jobs/worker.ts
+import { Cron } from "croner";
+import { listMachines } from "../services/machines.js";
+import { refreshMachine } from "../services/refresh.js";
+
+let job: Cron | null = null;
+
+/** Rafraîchit toutes les machines toutes les 30 minutes (tâche de fond). */
+export function startWorker(): void {
+  job = new Cron("*/30 * * * *", async () => {
+    for (const m of listMachines()) {
+      try {
+        await refreshMachine(m.id);
+      } catch (err) {
+        console.error(`[worker] refresh échoué pour ${m.id}:`, (err as Error).message);
+      }
+    }
+  });
+}
+
+export function stopWorker(): void {
+  job?.stop();
+  job = null;
+}