fix(desktop): require successful Telegram connection before Continue

Continue button is now disabled until the bot status is 'running'.
Skip remains available when no token has been entered.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/desktop/src/renderer/src/pages/onboarding/connect.tsx

@@ -143,7 +143,7 @@ export default function ConnectStep() {
                 Skip
               </Button>
             )}
-            <Button size="lg" onClick={handleContinue}>
+            <Button size="lg" onClick={handleContinue} disabled={!isRunning}>
               Continue
             </Button>
           </div>