fix: enable update checks in dev mode via forceDevUpdateConfig

Add dev-app-update.yml so electron-updater can check GitHub releases
even when running with bun run dev. Remove the isPackaged guard from
checkForUpdates() so manual clicks always contact the update server.
Automatic periodic checks remain disabled in dev mode.

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

src/main/services/autoUpdater.ts

@@ -23,6 +23,7 @@ type AutoUpdateListener = (...args: any[]) => void;
 interface AutoUpdaterLike {
   autoDownload: boolean;
   autoInstallOnAppQuit: boolean;
+  forceDevUpdateConfig: boolean;
   on(event: string, listener: AutoUpdateListener): this;
   removeListener(event: string, listener: AutoUpdateListener): this;
   checkForUpdates(): Promise<unknown>;
@@ -180,6 +181,7 @@ export class AutoUpdateService {
     this.scheduler = options.scheduler ?? defaultScheduler;
     this.updater.autoDownload = true;
     this.updater.autoInstallOnAppQuit = false;
+    this.updater.forceDevUpdateConfig = !options.isPackaged;
 
     this.updater.on('checking-for-update', this.checkingListener);
     this.updater.on('update-available', this.availableListener);
@@ -215,10 +217,6 @@ export class AutoUpdateService {
   }
 
   async checkForUpdates(): Promise<UpdateStatus> {
-    if (!this.options.isPackaged) {
-      return this.getStatus();
-    }
-
     if (this.pendingCheck) {
       return this.pendingCheck;
     }