Revert "Always revalidate desktop updates before install"

This reverts commit 7d80fdfd12.

packages/desktop/src/features/auto-updater.ts

@@ -76,16 +76,31 @@ export function getStagingUserId(): Promise<string> {
   return cachedStagingUserIdPromise;
 }
 
+// AppImages have no install step. electron-updater "installs" by unlinking the
+// running file and mv-ing the downloaded one into place; on app quit it does this
+// via a *blocking* execFileSync(newAppImage, { APPIMAGE_EXIT_AFTER_INSTALL: "true" }).
+// That env var is only honored by AppImageLauncher, so without it the freshly
+// launched process boots the full app and never exits — the quit hangs forever,
+// with the old binary already deleted. We therefore install AppImages only on
+// explicit quitAndInstall (the "Update now" button), which takes the non-blocking
+// spawn path. Every other target keeps auto-install-on-quit, which works there.
+export function shouldAutoInstallOnQuit(input: {
+  platform: NodeJS.Platform;
+  isAppImage: boolean;
+}): boolean {
+  return !(input.platform === "linux" && input.isAppImage);
+}
+
 class ElectronAppUpdateRuntime implements AppUpdateRuntime {
   private configured = false;
 
   configure(input: AppUpdateRuntimeConfiguration): void {
     autoUpdater.autoDownload = true;
     autoUpdater.autoRunAppAfterInstall = true;
-    // Paseo revalidates the current manifest before explicitly installing on quit.
-    // Electron's built-in handler would install an older download without checking
-    // whether a newer release has superseded it.
-    autoUpdater.autoInstallOnAppQuit = false;
+    autoUpdater.autoInstallOnAppQuit = shouldAutoInstallOnQuit({
+      platform: process.platform,
+      isAppImage: Boolean(process.env.APPIMAGE),
+    });
     autoUpdater.allowPrerelease = input.releaseChannel === "beta";
     autoUpdater.channel = input.releaseChannel === "beta" ? "beta" : "latest";
     autoUpdater.allowDowngrade = false;
@@ -179,13 +194,3 @@ export async function downloadAndInstallUpdate(
     onBeforeQuit,
   );
 }
-
-export async function installAppUpdateOnQuit({
-  currentVersion,
-  releaseChannel,
-}: {
-  currentVersion: string;
-  releaseChannel: AppReleaseChannel;
-}): Promise<boolean> {
-  return appUpdateService.installUpdateOnQuit({ currentVersion, releaseChannel });
-}