fix: enable background update checks in dev builds

Remove the isPackaged guard from AutoUpdateService.start() so that
background update checks run in both packaged and dev builds.
forceDevUpdateConfig already handles dev-mode config correctly via
dev-app-update.yml — the start() gate was preventing the 10s initial
check and 4h periodic checks from ever being scheduled in dev.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/main/services/autoUpdater.ts

@@ -192,7 +192,7 @@ export class AutoUpdateService {
   }
 
   start(): void {
-    if (this.started || !this.options.isPackaged) {
+    if (this.started) {
       return;
     }
 

tests/main/autoUpdater.test.ts

@@ -64,18 +64,20 @@ class FakeScheduler implements AutoUpdateScheduler {
 }
 
 describe('AutoUpdateService', () => {
-  test('does not schedule checks for unpackaged apps but manual checks still work', async () => {
+  test('schedules checks for unpackaged apps using dev update config', async () => {
     const updater = new FakeUpdater();
     const scheduler = new FakeScheduler();
     const service = new AutoUpdateService({ isPackaged: false, scheduler, updater });
 
     service.start();
 
-    expect(scheduler.timeouts).toHaveLength(0);
-    expect(scheduler.intervals).toHaveLength(0);
     expect(updater.forceDevUpdateConfig).toBe(true);
+    expect(scheduler.timeouts).toEqual([{ callback: expect.any(Function), delayMs: 10_000 }]);
+    expect(scheduler.intervals).toEqual([{ callback: expect.any(Function), delayMs: 4 * 60 * 60 * 1000 }]);
+
+    await scheduler.runTimeout();
+    await Promise.resolve();
 
-    await service.checkForUpdates();
     expect(updater.checkForUpdatesCalls).toBe(1);
   });