Migrate backend to Porto architecture and fix minor bugs

- Fully transitioned the backend to the Porto architectural pattern
- Improved code organization and maintainability
- Fixed minor bugs and inconsistencies

app/Containers/User/Models/Invitation.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace App\Containers\User\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+
+class Invitation extends Model
+{
+    use HasFactory;
+
+    protected $guarded = false;
+}