Enhance user role management and update Filament panel middleware

- Added new user roles: operator, operator_card, operator_loan, client, and currency_maintainer in ShieldSeeder.
- Included EnsureUserHasRole middleware in the Filament panel for improved access control.

app/Http/Middleware/EnsureUserHasRole.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace App\Http\Middleware;
+
+use Closure;
+use Illuminate\Http\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+class EnsureUserHasRole
+{
+    /**
+     * Handle an incoming request.
+     *
+     * @param  \Closure(\Illuminate\Http\Request): (\Symfony\Component\HttpFoundation\Response)  $next
+     */
+    public function handle(Request $request, Closure $next): Response
+    {
+        // if user does not have any role, add role "client"
+        /** @var \App\Models\User */
+        $user = $request->user();
+
+        if ($user->roles->count() == 0) {
+            $user->assignRole('client');
+        }
+
+        return $next($request);
+    }
+}