feat: add async prerequisite installation with retry logic and visual feedback

This commit enhances the boarding flow to handle prerequisite installation asynchronously with proper retry logic and user feedback:

- Add retry mechanism with max 3 attempts for prerequisite installation
- Display live installation logs via ActivityMonitor during boarding
- Reset ActivityMonitor state when starting new activity to prevent stale event dispatching
- Support dynamic header updates in ActivityMonitor
- Add prerequisitesInstalled event handler to revalidate after installation completes
- Extract validation logic into continueValidation() method for cleaner flow
- Add unit tests for prerequisite installation logic

This improves UX by showing users real-time progress during prerequisite installation and handles installation failures gracefully with automatic retries.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/Livewire/ActivityMonitor.php

@@ -28,12 +28,20 @@ class ActivityMonitor extends Component
 
     protected $listeners = ['activityMonitor' => 'newMonitorActivity'];
 
-    public function newMonitorActivity($activityId, $eventToDispatch = 'activityFinished', $eventData = null)
+    public function newMonitorActivity($activityId, $eventToDispatch = 'activityFinished', $eventData = null, $header = null)
     {
+        // Reset event dispatched flag for new activity
+        self::$eventDispatched = false;
+
         $this->activityId = $activityId;
         $this->eventToDispatch = $eventToDispatch;
         $this->eventData = $eventData;
 
+        // Update header if provided
+        if ($header !== null) {
+            $this->header = $header;
+        }
+
         $this->hydrateActivity();
 
         $this->isPollingActive = true;