feat: add day-5 branded payment-failure reminder mailable

resources/views/emails/payment-failed-day-5.blade.php

@@ -0,0 +1,27 @@
+<x-mail::message>
+# Your {{ ucfirst($tier) }} features end tomorrow
+
+Hi {{ $name }},
+
+Stripe has been trying to renew your subscription for the past few days without
+success. If the next retry doesn't go through, your **{{ ucfirst($tier) }}**
+subscription will be cancelled tomorrow and your account will move back to the
+Free tier.
+
+Here's what you'll lose on Free:
+
+- Smart fill-up / wait recommendations
+- Multi-channel alerts (WhatsApp, SMS, push)
+- Advanced fuel-price predictions
+
+You can keep everything running by updating your card now:
+
+<x-mail::button :url="$portalUrl">
+    Update payment method
+</x-mail::button>
+
+If you meant to cancel, no action needed — you'll just drop to Free automatically.
+
+Thanks for using FuelAlert,
+The FuelAlert Team
+</x-mail::message>