fix(stripe): add error handling and resilience to subscription operations

- Record refunds immediately before cancellation to prevent retry issues if cancel fails
- Wrap Stripe API calls in try-catch for refunds and quantity reverts with internal notifications
- Add null check in Team.subscriptionEnded() to prevent NPE when subscription doesn't exist
- Fix control flow bug in StripeProcessJob (add missing break statement)
- Cap dynamic server limit with MAX_SERVER_LIMIT in subscription updates
- Add comprehensive tests for refund failures, event handling, and null safety

app/Models/Team.php

@@ -197,6 +197,10 @@ class Team extends Model implements SendsDiscord, SendsEmail, SendsPushover, Sen
 
     public function subscriptionEnded()
     {
+        if (! $this->subscription) {
+            return;
+        }
+
         $this->subscription->update([
             'stripe_subscription_id' => null,
             'stripe_cancel_at_period_end' => false,