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/Mails/InvitationMail.php

@@ -0,0 +1,62 @@
+<?php
+
+namespace App\Containers\User\Mails;
+
+use App\Containers\User\Models\Invitation;
+use Illuminate\Bus\Queueable;
+use Illuminate\Mail\Mailable;
+use Illuminate\Mail\Mailables\Content;
+use Illuminate\Mail\Mailables\Envelope;
+use Illuminate\Queue\SerializesModels;
+use Illuminate\Support\Facades\URL;
+
+class InvitationMail extends Mailable
+{
+    use Queueable, SerializesModels;
+
+
+    private Invitation $invitation;
+    /**
+     * Create a new message instance.
+     */
+    public function __construct(Invitation $invitation)
+    {
+        $this->invitation = $invitation;
+    }
+
+    /**
+     * Get the message envelope.
+     */
+    public function envelope(): Envelope
+    {
+        return new Envelope(
+            subject: 'Invitation Mail',
+        );
+    }
+
+    /**
+     * Get the message content definition.
+     */
+    public function content(): Content
+    {
+        return new Content(
+            markdown: 'emails.invitation',
+            with: [
+                'acceptUrl' => URL::signedRoute(
+                    'invitation.accept',
+                    ['invitation' => $this->invitation]
+                )
+            ],
+        );
+    }
+
+    /**
+     * Get the attachments for the message.
+     *
+     * @return array<int, \Illuminate\Mail\Mailables\Attachment>
+     */
+    public function attachments(): array
+    {
+        return [];
+    }
+}