feat: Refactor user management to replace email with username across the application

src/app/admin/users/page.js

@@ -194,7 +194,7 @@ export default function UserManagementPage() {
 												</div>
 												<div>
 													<h3 className="text-lg font-semibold text-gray-900">{user.name}</h3>
-													<p className="text-sm text-gray-500">{user.email}</p>
+													<p className="text-sm text-gray-500">{user.username}</p>
 												</div>
 											</div>
 											<div className="flex items-center space-x-2">
@@ -284,7 +284,7 @@ export default function UserManagementPage() {
 function CreateUserModal({ onClose, onUserCreated }) {
 	const [formData, setFormData] = useState({
 		name: "",
-		email: "",
+		username: "",
 		password: "",
 		role: "user",
 		is_active: true
@@ -353,12 +353,12 @@ function CreateUserModal({ onClose, onUserCreated }) {
 
 					<div>
 						<label className="block text-sm font-medium text-gray-700 mb-1">
-							Email
+							Username
 						</label>
 						<Input
-							type="email"
-							value={formData.email}
-							onChange={(e) => setFormData({ ...formData, email: e.target.value })}
+							type="text"
+							value={formData.username}
+							onChange={(e) => setFormData({ ...formData, username: e.target.value })}
 							required
 						/>
 					</div>