feat(desktop): poll for updates every 4 hours while running

Boot-time check alone left idle sessions stuck on outdated builds. Add a
recurring interval check; the existing update-downloaded dialog still
drives the actual restart.

Author: RhysSullivan

.changeset/desktop-periodic-update-check.md

@@ -0,0 +1,10 @@
+---
+"@executor-js/desktop": patch
+"executor": patch
+---
+
+Desktop now re-checks for updates every 4 hours while running. Previously
+the only update check was at app launch, so a long-running session would
+sit on an outdated build indefinitely until the user quit and relaunched.
+The interval is a self-heal — once an update is downloaded, the existing
+"Update ready" dialog drives the rest of the flow.

apps/desktop/src/main/index.ts

@@ -302,6 +302,11 @@ const promptInstallUpdate = async (version: string) => {
   }
 };
 
+// Re-check periodically so a long-running session picks up releases
+// without requiring a quit + relaunch. The boot-time check still runs;
+// this interval is purely a self-heal for idle apps.
+const UPDATE_POLL_INTERVAL_MS = 4 * 60 * 60 * 1000; // 4 hours
+
 const setupAutoUpdater = () => {
   if (!app.isPackaged) return;
   autoUpdater.logger = log;
@@ -315,6 +320,11 @@ const setupAutoUpdater = () => {
   autoUpdater.on("error", (err: Error) => {
     log.warn("[updater] error", err);
   });
+
+  setInterval(() => {
+    if (downloadedUpdateVersion) return; // already staged; waiting on the user
+    void runUpdateCheck({ alertOnFail: false });
+  }, UPDATE_POLL_INTERVAL_MS);
 };
 
 interface UpdateCheckOptions {