test: App mode - Execution tests (#10801)

## Summary

Adds tests that simulate the execution flow and output feed

## Changes

- **What**: 
- Add ExecutionHelper for mocking network activity
- Refactor ws fixture to use Playwright websocket helper instead of
patching window
- 

## Review Focus

<!-- Critical design decisions or edge cases that need attention -->

<!-- If this PR fixes an issue, uncomment and update the line below -->
<!-- Fixes #ISSUE_NUMBER -->

## Screenshots (if applicable)

<!-- Add screenshots or video recording to help explain your changes -->

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10801-test-App-mode-Execution-tests-3356d73d365081e4acf0c34378600031)
by [Unito](https://www.unito.io)

apps/website/src/components/GetStartedSection.vue

@@ -40,7 +40,7 @@ const steps = computed(() => [
           <!-- Connecting line between steps (desktop only) -->
           <div
             v-if="index < steps.length - 1"
-            class="absolute right-0 top-8 hidden w-full translate-x-1/2 border-t border-brand-yellow/20 md:block"
+            class="absolute top-8 right-0 hidden w-full translate-x-1/2 border-t border-brand-yellow/20 md:block"
           />
 
           <div class="relative">