fully remove email sending options and everything about stmp from this code : <?php
session_start();
require 'db.php';

// Include PHPMailer files (adjust path if needed)
require 'PHPMailer/src/Exception.php';
require 'PHPMailer/src/PHPMailer.php';
require 'PHPMailer/src/SMTP.php';

use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;

$login_error = '';
$register_error = '';
$register_success = '';

// Handle login
if (isset($_POST['login'])) {
    $username = trim($_POST['username']);
    $password = $_POST['password'];

    // Fetch user by username
    $stmt = $pdo->prepare("SELECT * FROM users WHERE username = ?");
    $stmt->execute([$username]);
    $user = $stmt->fetch();

    if ($user && password_verify($password, $user['password'])) {
        // Set session variables
        $_SESSION['user_id'] = $user['id'];
        $_SESSION['username'] = $user['username'];
        $_SESSION['full_name'] = $user['full_name'];
        $_SESSION['is_admin'] = $user['is_admin'] ?? 0;

        // Redirect based on admin status
        if ($_SESSION['is_admin'] == 1) {
            header("Location: admin.php");
        } else {
            header("Location: dashboard.php");
        }
        exit;
    } else {
        $login_error = "نام کاربری یا رمزعبور اشتباه است.";
    }
}

// Handle registration
if (isset($_POST['register'])) {
    $full_name = trim($_POST['full_name']);
    $username = trim($_POST['username']);
    $password_raw = $_POST['password'];
    $email = filter_var(trim($_POST['email']), FILTER_VALIDATE_EMAIL);

    // Input validation
    if (empty($full_name) || empty($username) || empty($password_raw) || !$email) {
        $register_error = "لطفاً تمام فیلدها را به درستی پر کنید.";
    } else {
        // Check if email exists
        $stmt = $pdo->prepare("SELECT id FROM users WHERE email = ?");
        $stmt->execute([$email]);
        if ($stmt->rowCount() > 0) {
            $register_error = "این ایمیل قبلاً ثبت شده است.";
        } else {
            // Check if username exists
            $stmt = $pdo->prepare("SELECT id FROM users WHERE username = ?");
            $stmt->execute([$username]);

            if ($stmt->rowCount() > 0) {
                $register_error = "این نام کاربری قبلاً گرفته شده است.";
            } else {
                $password = password_hash($password_raw, PASSWORD_DEFAULT);
                // Insert new user with email
                $stmt = $pdo->prepare("INSERT INTO users 
                    (full_name, username, password, email, max_students, students_uploaded)
                    VALUES (?, ?, ?, ?, 400, 0)");

                if ($stmt->execute([$full_name, $username, $password, $email])) {
                    $userId = $pdo->lastInsertId();

                    // Generate token & set expiration
                    $token = bin2hex(random_bytes(50));
                    $expires = date('Y-m-d H:i:s', strtotime('+1 hour'));

                    // Save token to DB
                    $stmt = $pdo->prepare("UPDATE users SET verification_token = ?, verification_expires = ? WHERE id = ?");
                    $stmt->execute([$token, $expires, $userId]);

                    // Build verification URL (change domain accordingly)
                    $verifyUrl = "http://yourdomain.com/verify_email.php?token=$token";

                    // Send email using PHPMailer
                    $mail = new PHPMailer(true);

                    try {
                        // Server settings
                        $mail->isSMTP();
                        $mail->Host = 'smtp.gmail.com';
                        $mail->SMTPAuth = true;
                        $mail->Username = 'arsalan41maleki@gmail.com';            // your Gmail address
                        $mail->Password = 'tjdy gmdf tlgn qssg
';               // the app password you just generated
                        $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;  // Encryption TLS
                        $mail->Port = 587;

                        // Recipients
                        $mail->setFrom('no-reply@yourdomain.com', 'سامانه دانش آموزان');
                        $mail->addAddress($email, $full_name);

                        // Content
                        $mail->isHTML(false);
                        $mail->Subject = "تایید ایمیل - سامانه دانش آموزان";
                        $mailBody = "سلام $full_name,\n\n" .
                            "لطفاً ایمیل خود را با کلیک روی لینک زیر تایید کنید:\n$verifyUrl\n\n" .
                            "این لینک بعد از یک ساعت منقضی می‌شود.";
                        $mail->Body = $mailBody;

                        $mail->send();
                        $register_success = "✅ ایمیل تایید برای شما ارسال شد.";
                    } catch (Exception $e) {
                        $register_error = "ثبت نام موفقیت‌آمیز بود، اما ایمیل ارسال نشد. خطا: {$mail->ErrorInfo}";
                    }
                } else {
                    $register_error = "ثبت نام با خطا مواجه شد.";
                }
            }
        }
    }
}
?>
<!DOCTYPE html>
<html lang="fa" dir="rtl">
<head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <title>ورود و ثبت نام | سامانه دانش آموزان</title>
    <style>
        @font-face {
            font-family: 'IranSans';
            src: url('IranSans.woff2') format('woff2'),
                 url('IranSans.woff') format('woff'),
                 url('IranSans.ttf') format('truetype');
            font-weight: normal;
            font-style: normal;
            font-display: swap;
        }
        * {
            font-family: 'IranSans', Tahoma, Arial, sans-serif !important;
            box-sizing: border-box;
        }
        body, html {
            margin: 0; padding: 0;
            height: 100%;
            background: linear-gradient(135deg, #1e3c72, #2a5298);
            overflow-x: hidden;
            color: #eee;
        }
        #particles-js {
          position: fixed;
          top:0; left:0;
          width: 100%; height: 100%;
          z-index: 0;
          pointer-events: none;
        }
        .container {
            min-height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 20px;
            position: relative;
            z-index: 10;
        }
        .auth-wrapper {
            width: 100%;
            max-width: 900px;
            background: rgba(30, 60, 114, 0.9);
            border-radius: 14px;
            box-shadow: 0 8px 30px rgba(0,0,0,0.7);
            display: flex;
            gap: 0;
            overflow: hidden;
            flex-wrap: wrap;
        }
        .auth-box {
            flex: 1 1 400px;
            padding: 40px 45px;
            display: flex;
            flex-direction: column;
            justify-content: center;
            min-width: 320px;
        }
        .auth-box + .auth-box {
            border-right: 2px solid #2a5298;
            border-left: 2px solid #2a5298;
        }
        h2 {
            font-weight: 900;
            font-size: 2.4rem;
            margin-bottom: 30px;
            color: #f0f6fc;
            user-select: none;
            text-align: center;
        }
        form {
            width: 100%;
            display: flex;
            flex-direction: column;
            gap: 20px;
            user-select: none;
        }
        input[type="text"], input[type="password"], input[type="email"] {
            padding: 14px 18px;
            border-radius: 10px;
            border: none;
            font-size: 1rem;
            font-weight: 600;
            outline: none;
            transition: box-shadow 0.3s ease;
            letter-spacing: 0.05em;
            direction: rtl;
            color: #222;
        }
        input[type="text"]::placeholder,
        input[type="password"]::placeholder,
        input[type="email"]::placeholder {
            color: #999;
            font-weight: 500;
        }
        input[type="text"]:focus,
        input[type="password"]:focus,
        input[type="email"]:focus {
            box-shadow: 0 0 8px 3px #3bbcffaa;
        }
        button {
            background-color: #3bbcff;
            border: none;
            padding: 14px 0;
            font-size: 1.1rem;
            font-weight: 900;
            color: #fff;
            border-radius: 12px;
            cursor: pointer;
            transition: background-color 0.3s ease;
            user-select: none;
            margin-top: 10px;
            letter-spacing: 0.1em;
        }
        button:hover {
            background-color: #28a3e7;
        }
        .message {
            text-align: center;
            padding: 12px 10px;
            border-radius: 10px;
            margin-bottom: 20px;
            line-height: 1.3;
            font-weight: 600;
            user-select: text;
        }
        .message.error {
            background-color: #ff4c4c;
            color: #fff;
            box-shadow: 0 0 12px #ff000060;
        }
        .message.success {
            background-color: #4caf50;
            color: #fff;
            box-shadow: 0 0 12px #27ae601a;
        }

        /* Responsive */
        @media (max-width: 900px) {
            .auth-wrapper {
                flex-direction: column;
            }
            .auth-box + .auth-box {
                border: none;
                border-top: 2px solid #2a5298;
            }
        }

    </style>
</head>
<body>

<div id="particles-js"></div>

<div class="container">
    <div class="auth-wrapper" role="main">
        <!-- Login box -->
        <section class="auth-box" aria-labelledby="login-title">
            <h2 id="login-title" tabindex="0">ورود به سامانه</h2>
            <?php if (!empty($login_error)): ?>
                <p class="message error" role="alert" aria-live="assertive"><?=htmlspecialchars($login_error)?></p>
            <?php endif; ?>
            <form method="post" novalidate>
                <input 
                    type="text" 
                    name="username" 
                    placeholder="نام کاربری" 
                    autocomplete="username" 
                    required 
                    aria-required="true"
                    />
                <input 
                    type="password" 
                    name="password" 
                    placeholder="گذرواژه" 
                    autocomplete="current-password" 
                    required 
                    aria-required="true"
                    />
                <button type="submit" name="login" aria-label="ورود به سامانه">ورود</button>
            </form>
        </section>

        <!-- Register box -->
        <section class="auth-box" aria-labelledby="register-title">
            <h2 id="register-title" tabindex="0">ثبت نام در سامانه</h2>
            <?php if (!empty($register_error)): ?>
                <p class="message error" role="alert" aria-live="assertive"><?=htmlspecialchars($register_error)?></p>
            <?php elseif (!empty($register_success)): ?>
                <p class="message success" role="alert" aria-live="assertive"><?=htmlspecialchars($register_success)?></p>
            <?php endif; ?>
            <form method="post" novalidate>
                <input 
                    type="text" 
                    name="full_name" 
                    placeholder="نام و نام خانوادگی" 
                    autocomplete="name" 
                    required 
                    aria-required="true"
                    />
                <input 
                    type="text" 
                    name="username" 
                    placeholder="نام کاربری" 
                    autocomplete="username" 
                    required 
                    aria-required="true"
                    />
                <input 
                    type="password" 
                    name="password" 
                    placeholder="گذرواژه" 
                    autocomplete="new-password" 
                    required 
                    aria-required="true"
                    />
                <input 
                    type="email" 
                    name="email" 
                    placeholder="ایمیل" 
                    autocomplete="email" 
                    required 
                    aria-required="true"
                    />
                <button type="submit" name="register" aria-label="ثبت نام در سامانه">ثبت نام</button>
            </form>
        </section>
    </div>
</div>

<script src="https://cdn.jsdelivr.net/npm/particles.js@2.0.0/particles.min.js"></script>
<script>
  particlesJS('particles-js',
  {
    "particles": {
      "number": {
        "value": 70,
        "density": {
          "enable": true,
          "value_area": 900
        }
      },
      "color": {
        "value": "#fff"
      },
      "shape": {
        "type": "circle"
      },
      "opacity": {
        "value": 0.45,
        "random": true,
        "anim": {
          "enable": false
        }
      },
      "size": {
        "value": 3,
        "random": true
      },
      "line_linked": {
        "enable": true,
        "distance": 120,
        "color": "#fff",
        "opacity": 0.3,
        "width": 1
      },
      "move": {
        "enable": true,
        "speed": 3,
        "direction": "none",
        "random": false,
        "straight": false,
        "out_mode": "out"
      }
    },
    "interactivity": {
      "detect_on": "canvas",
      "events": {
        "onhover": {
          "enable": true,
          "mode": "grab"
        },
        "onclick": {
          "enable": true,
          "mode": "push"
        }
      },
      "modes": {
        "grab": {
          "distance": 180,
          "line_linked": {
            "opacity": 0.7
          }
        },
        "push": {
          "particles_nb": 5
        }
      }
    },
    "retina_detect": true
  });
</script>

</body>
</html>