perf: paginate docs list, lazy thumbnails, static cache headers

templates/base.html

@@ -50,10 +50,12 @@
           <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M14 2H6a2 2 0 0 0-2 2v16a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2V8z"/><polyline points="14 2 14 8 20 8"/><line x1="16" y1="13" x2="8" y2="13"/><line x1="16" y1="17" x2="8" y2="17"/></svg>
           قائمة الوثائق
         </a>
+        {% if request.state.user and request.state.user.role == 'admin' %}
         <a href="/auth/users" class="nav-link">
           <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M12 15c-4 0-7 2-7 4v1h14v-1c0-2-3-4-7-4z"/><circle cx="12" cy="8" r="4"/></svg>
           الإدارة
         </a>
+        {% endif %}
         <a href="/auth/logout" class="nav-link nav-link-logout">
           <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M9 21H5a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h4"/><polyline points="16 17 21 12 16 7"/><line x1="21" y1="12" x2="9" y2="12"/></svg>
           خروج