feat: Reimplement order and invoice management with new service and repository layers, introduce compression middleware, and update database schema.

app/Models/ServiceAddon.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+
+class ServiceAddon extends Model
+{
+    use HasFactory;
+
+    protected $table = 'service_addons';
+
+    protected $guarded = [];
+
+    // -------------------------------------------------------------------------
+    // Relationships
+    // -------------------------------------------------------------------------
+
+    public function service()
+    {
+        return $this->belongsTo(Service::class, 'service_id');
+    }
+}