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

tests/Feature/Subscription/TeamSubscriptionEndedTest.php

@@ -0,0 +1,16 @@
+<?php
+
+use App\Models\Team;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+
+uses(RefreshDatabase::class);
+
+test('subscriptionEnded does not throw when team has no subscription', function () {
+    $team = Team::factory()->create();
+
+    // Should return early without error — no NPE
+    $team->subscriptionEnded();
+
+    // If we reach here, no exception was thrown
+    expect(true)->toBeTrue();
+});