fix inconsistencies in page layout, add swiss clock

hbd/server/templates/nav.html

@@ -10,6 +10,9 @@
     <a href="/settings"{% if active_page == "settings" %} class="active"{% endif %}>Settings</a>
     {% endif %}
   </div>
+  <div class="nav-clock" title="Click for full-screen clock">
+    <canvas id="swiss-clock" width="44" height="44"></canvas>
+  </div>
   {% if current_user %}
   <a href="/profile" class="nav-user{% if active_page == 'profile' %} active{% endif %}" title="{{ current_user.full_name or current_user.username }}">
     {% if current_user.avatar %}
@@ -21,6 +24,12 @@
   </a>
   {% endif %}
 </div>
+
+<!-- Full-page clock overlay (click anywhere to dismiss) -->
+<div id="clock-overlay">
+  <canvas id="swiss-clock-overlay" width="400" height="400"></canvas>
+</div>
+
 <script>
   (function() {
     var btn = document.getElementById('nav-hamburger-btn');