feat(subscription): add Stripe action controls

Add subscription action handling and tests for cancel, resume, and refund flows while resolving StripeClient through the container.

app/Actions/Stripe/UpdateSubscriptionQuantity.php

@@ -17,7 +17,7 @@ class UpdateSubscriptionQuantity
 
     public function __construct(?StripeClient $stripe = null)
     {
-        $this->stripe = $stripe ?? new StripeClient(config('subscription.stripe_api_key'));
+        $this->stripe = $stripe ?? app(StripeClient::class);
     }
 
     /**