fix(go): wrap adults table in <div class="table-container">

The lifted CSS defines .table-container with border: 1px solid #333 and
max-width: 1200px — without the wrapper the table stretched to full
viewport width and showed no border. Mirrors templates/adults.html.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

go/internal/web/templates/adults.tmpl

@@ -42,6 +42,7 @@
 </div>
 
 {{if .Data.Results}}
+<div class="table-container">
 <table>
   <thead>
     <tr>
@@ -85,6 +86,7 @@
     </tr>
   </tbody>
 </table>
+</div>
 {{else}}
 <div class="description">No members found.</div>
 {{end}}