Block unverified users from marking themselves ready

GameDashboardService::toggleReady() now rejects the toggle if the
user's email isn't verified (mirrors the same gate UserChecker already
applies at login). The waiting-room checkbox is disabled client-side
with an explanatory alert and a link to resend the verification email,
and the controller adds a flash error as a server-side fallback if it
somehow gets submitted anyway.

templates/game/waiting.html.twig

@@ -56,9 +56,15 @@
 
                 <hr>
 
+                {% if not app.user.verified %}
+                    <div class="alert alert-warning">
+                        You must verify your email address before you can mark yourself as ready.
+                        Check your inbox for the confirmation link, or <a href="{{ path('app_verify_resend_email') }}">request a new one</a>.
+                    </div>
+                {% endif %}
                 <form method="post" class="mt-4">
                     <div class="form-check form-switch mb-3">
-                        <input class="form-check-input" type="checkbox" id="toggle_ready" name="toggle_ready" onchange="this.form.submit()" {{ isReady ? 'checked' : '' }}>
+                        <input class="form-check-input" type="checkbox" id="toggle_ready" name="toggle_ready" onchange="this.form.submit()" {{ isReady ? 'checked' : '' }} {{ not app.user.verified ? 'disabled' : '' }}>
                         <label class="form-check-label" for="toggle_ready">
                             <strong>I am ready to start!</strong>
                         </label>