Enabled NetmailPolicy, users can see netmail if they are in the seen-by, a ZC or admin

app/Policies/EchomailPolicy.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace App\Policies;
+
+use Illuminate\Auth\Access\HandlesAuthorization;
+
+use App\Models\{Echomail,User};
+
+class EchomailPolicy
+{
+	use HandlesAuthorization;
+
+	/**
+	 * This determines whether a logged-in user can view an echomail
+	 *
+	 * @param User $user
+	 * @param Echomail $o
+	 * @return bool
+	 */
+	public function view(User $user, Echomail $o): bool
+	{
+		return (
+			$user->isAdmin()
+			|| $user->isZC()
+			|| $o->seenby->pluck('id')->intersect($user->addresses()->pluck('id'))->count()
+		);
+	}
+}