test(desktop): stabilize updater preference test against slow-disk race

The "skips startup and periodic checks when automatic updates are
disabled" case advanced fake timers without awaiting the async
preference load. On slow CI the in-flight readFile resolved after
afterEach() removed the temp dir, defaulted enabled back to true, and
fired a deferred background check into the next test's freshly-cleared
shared mock — making "persists the automatic update preference and stops
future background checks" flake with checkForUpdates called once.

Await updater:get-preferences (which awaits preferencesReady) before
advancing timers so the read settles against the existing file and no
background work outlives the test. Test-only change; production behavior
is unaffected.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Co-authored-by: multica-agent <github@multica.ai>

apps/desktop/src/main/updater.test.ts

@@ -160,6 +160,12 @@ describe("setupAutoUpdater", () => {
     );
     setupAutoUpdater(() => null);
 
+    // Let the async preference load settle before advancing timers; otherwise
+    // the in-flight readFile can resolve after afterEach() removes the temp
+    // dir, default back to enabled=true, and fire a background check into the
+    // next test's freshly-cleared mock (flake on slow CI).
+    await invokeIpc("updater:get-preferences");
+
     await vi.advanceTimersByTimeAsync(60 * 60 * 1000 + 5_000);
 
     expect(ctx.checkForUpdates).not.toHaveBeenCalled();