Add freemium plans, wallet-billed host notifications, and Pro upgrades.

Host alerts use email/phone on the host record without requiring a Ladill
account link; SMS and over-quota emails debit the org wallet at platform rates.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/Models/NotificationUsage.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class NotificationUsage extends Model
+{
+    protected $table = 'frontdesk_notification_usage';
+
+    protected $fillable = [
+        'organization_id', 'period', 'email_count', 'sms_count',
+        'email_charged_minor', 'sms_charged_minor',
+    ];
+
+    public function organization(): BelongsTo
+    {
+        return $this->belongsTo(Organization::class, 'organization_id');
+    }
+}