Refactor admin panel: enhance user management and security features

- Added role-based access control for user management links in admin navigation.
- Improved user account display with a dedicated account link.
- Implemented form submission confirmation for delete actions in the admin interface.
- Introduced a password visibility toggle on the login page.
- Added login throttling to prevent brute-force attacks, recording failed attempts.
- Created a CLI script for creating an admin user, replacing the previous hardcoded admin credentials.
- Updated database schema to support login attempt tracking.
- Enhanced user editing functionality, allowing role changes with restrictions.
- Improved modal handling for user actions, ensuring better focus management.
- Added styles for new account management page and improved modal transitions.

admin/index.php

@@ -122,12 +122,14 @@ $announcements = get_all_announcements();
       <div class="admin-nav-links">
         <a href="index.php" class="active">Announcements</a>
         <a href="menu.php">Menu</a>
+        <?php if (($user['role'] ?? '') === 'admin'): ?>
         <a href="users.php">Users</a>
+        <?php endif; ?>
         <a href="hours.php">Hours</a>
       </div>
       <div class="admin-user">
-        <span>Logged in as <strong><?= htmlspecialchars($user['username']) ?></strong></span>
         <a href="../" target="_blank" rel="noopener">View Public Site ↗</a>
+        <a href="account.php" class="admin-account-link" title="My Account"><?= htmlspecialchars($user['username']) ?></a>
         <a href="logout.php">Sign Out</a>
       </div>
     </div>
@@ -219,7 +221,7 @@ $announcements = get_all_announcements();
                       <div class="action-stack">
                         <a href="index.php?edit=<?= (int)$ann['id'] ?>" class="btn btn-outline btn-sm">Edit</a>
 
-                        <form method="POST" action="index.php" style="display: inline;" onsubmit="return confirm('Are you sure you want to delete this announcement?');">
+                        <form method="POST" action="index.php" style="display: inline;" class="js-confirm-submit" data-confirm="Are you sure you want to delete this announcement?">
                           <input type="hidden" name="action" value="delete_announcement">
                           <input type="hidden" name="csrf_token" value="<?= htmlspecialchars(get_csrf_token()) ?>">
                           <input type="hidden" name="announcement_id" value="<?= (int)$ann['id'] ?>">