refactor(templates): use timeago filter for admin/blueprint timestamps

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

l4d2web/l4d2web/templates/admin_users.html

@@ -22,8 +22,8 @@
         <td>{{ user.username }}</td>
         <td>{{ "yes" if user.admin else "no" }}</td>
         <td>{{ "yes" if user.active else "no" }}</td>
-        <td>{{ user.created_at }}</td>
+        <td>{{ user.created_at | timeago }}</td>
-        <td>{{ user.updated_at }}</td>
+        <td>{{ user.updated_at | timeago }}</td>
         <td>
           {% if user.id == g.user.id %}
             <span class="muted">you</span>

l4d2web/l4d2web/templates/blueprints.html

@@ -14,8 +14,8 @@
       {% for blueprint in blueprints %}
       <tr>
         <td><a href="/blueprints/{{ blueprint.id }}">{{ blueprint.name }}</a></td>
-        <td>{{ blueprint.created_at }}</td>
+        <td>{{ blueprint.created_at | timeago }}</td>
-        <td>{{ blueprint.updated_at }}</td>
+        <td>{{ blueprint.updated_at | timeago }}</td>
         <td><a href="/servers?blueprint_id={{ blueprint.id }}">Create server</a></td>
       </tr>
       {% else %}