feat(payment): implement beautiful payment confirmation page with real-time status checking

- Add PaymentSuccessController with authentication and subscription selection logic
   - Create PaymentConfirmation Livewire component with polling mechanism
   - Implement real-time subscription status verification via Polar provider API
   - Add confetti animation for successful payment confirmation
   - Design responsive payment success page with dark mode support
   - Fix Polar provider field mapping (updated_at -> modified_at)
   - Add comprehensive error handling and logging
   - Support multiple subscription status states (verifying, activated, pending, error)
   - Implement automatic polling with 30-second intervals (max 5 attempts)
   - Add fallback redirects and user-friendly status messages

app/Services/Payments/Providers/PolarProvider.php

@@ -461,10 +461,19 @@ class PolarProvider implements PaymentProviderContract
 
             if (! $response->successful()) {
                 Log::error('Failed to retrieve Polar subscription: '.$response->body());
+                throw new \Exception('Polar subscription not found: '.$response->status());
             }
 
             $polarSubscription = $response->json();
 
+            if (! $polarSubscription || ! isset($polarSubscription['id'])) {
+                Log::error('Invalid Polar subscription response', [
+                    'subscription_id' => $providerSubscriptionId,
+                    'response' => $polarSubscription,
+                ]);
+                throw new \Exception('Invalid Polar subscription response');
+            }
+
             return [
                 'id' => $polarSubscription['id'],
                 'status' => $polarSubscription['status'],
@@ -476,7 +485,7 @@ class PolarProvider implements PaymentProviderContract
                 'trial_start' => $polarSubscription['trial_start'] ?? null,
                 'trial_end' => $polarSubscription['trial_end'] ?? null,
                 'created_at' => $polarSubscription['created_at'],
-                'updated_at' => $polarSubscription['updated_at'],
+                'updated_at' => $polarSubscription['modified_at'] ?? null,
             ];
 
         } catch (\Exception $e) {