feat: Implement CSRF protection and basic form validation, streamline form data, and add comprehensive unit and E2E tests.

templates/form.html

@@ -18,7 +18,14 @@
         <h1 class="text-center mb-2">{{ event.title }}</h1>
         <p class="text-center text-muted mb-4">{{ event.description }}</p>
 
+        {% if error %}
+        <div class="alert alert-danger" role="alert">
+            {{ error }}
+        </div>
+        {% endif %}
+
         <form method="POST">
+            <input type="hidden" name="_csrf_token" value="{{ csrf_token() }}">
             <!-- Boot Info -->
             <h4 class="section-title">De Boot</h4>
             <div class="row g-3 mb-3">