Implemented the authenticated admin contact system.

app/Http/Controllers/SupportAttachmentController.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Models\SupportAttachment;
+use Illuminate\Http\Request;
+use Illuminate\Support\Facades\Storage;
+use Symfony\Component\HttpFoundation\StreamedResponse;
+
+class SupportAttachmentController extends Controller
+{
+    public function __invoke(Request $request, SupportAttachment $attachment): StreamedResponse
+    {
+        $attachment->loadMissing('message.conversation');
+
+        abort_unless(
+            $request->user()?->is_admin || $attachment->message->conversation->user_id === $request->user()?->id,
+            403,
+        );
+
+        return Storage::disk($attachment->disk)->download($attachment->path, $attachment->original_name);
+    }
+}