Add subscription tiers, notification preferences, and logging infrastructure

- Add database migrations for plans, subscriptions, notification preferences, and notification log tables
- Implement DispatchUserNotificationJob to handle channel resolution, daily limits, and logging (sent/tier_restricted/daily_limit)
- Add SendScheduledWhatsAppJob for scheduled notification delivery
- Create PlanFeatures service to resolve tier capabilities, check daily limits, and validate fuel

app/Enums/PlanTier.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace App\Enums;
+
+enum PlanTier: string
+{
+    case Free = 'free';
+    case Basic = 'basic';
+    case Plus = 'plus';
+    case Pro = 'pro';
+}