Refactor code: remove unnecessary comments and clean up whitespace in various files

php/process_login.php

@@ -1,23 +1,18 @@
-<!-- filepath: c:\xampp\htdocs\Spik-en-span\process_login.php -->
 <?php
-// Database connection
 $servername = "localhost";
-$username = "database12"; // Updated username
-$password = "181t$1lJg"; // Updated password
+$username = "database12";
+$password = "181t$1lJg";
 $dbname = "spik_en_span";
 
 $conn = new mysqli($servername, $username, $password, $dbname);
 
-// Check connection
 if ($conn->connect_error) {
     die("Connection failed: " . $conn->connect_error);
 }
 
-// Retrieve form data
 $username = isset($_POST['username']) ? trim(htmlspecialchars($_POST['username'])) : '';
 $password = isset($_POST['password']) ? trim(htmlspecialchars($_POST['password'])) : '';
 
-// Validate credentials
 $sql = "SELECT id, password_hash FROM employees WHERE username = ?";
 $stmt = $conn->prepare($sql);
 if ($stmt) {
@@ -32,13 +27,11 @@ if ($stmt) {
 
 try {
     if ($password_hash && password_verify($password, $password_hash)) {
-        // Start session and store user ID
         session_start();
         $_SESSION['user_id'] = $user_id;
-        header("Location: "); // Redirect to the QR scanner page
+        header("Location: ");
         exit();
     } else {
-        // Redirect back to login page with an error message
         header("Location: ../employee-login.php?error=invalid_credentials");
         exit();
     }