feat(web/topology): hide DELETE on running topologies

The DELETE path on a topology whose containers are still up is a
footgun — even if the backend rejects the delete, surfacing the
button invites mistakes. Gate it so DELETE only shows for pending,
failed, and torn-down topologies. Active/degraded/deploying topologies
must be torn down first, which then reveals DELETE again.

decnet_web/src/components/TopologyList/TopologyList.tsx

@@ -222,6 +222,7 @@ const TopologyList: React.FC = () => {
                   <Power size={10} /> {armed === `td:${r.id}` ? 'CONFIRM?' : 'TEARDOWN'}
                 </button>
               )}
+              {!['active', 'degraded', 'deploying'].includes(r.status) && (
                 <button
                   type="button"
                   className={`tlist-btn small danger ${armed === r.id ? 'armed' : ''}`}
@@ -231,6 +232,7 @@ const TopologyList: React.FC = () => {
                 >
                   <Trash2 size={10} /> {armed === r.id ? 'CONFIRM?' : 'DELETE'}
                 </button>
+              )}
             </div>
           </div>
         ))}