fix: mesh mobile header hidden + DID hover on node names

- Mesh: remove display:flex from .mesh-header CSS that overrode
  Tailwind hidden class, causing title/peers to show on mobile
- Federation: add title={did} on node name for hover tooltip
- Cloud: add title={did} on peer name for hover tooltip
- Both already show node.name when available, DID as fallback

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

neode-ui/src/views/Federation.vue

@@ -162,7 +162,7 @@
           <div class="flex items-center justify-between mb-2">
             <div class="flex items-center gap-3 min-w-0">
               <div class="w-2.5 h-2.5 rounded-full shrink-0" :class="isOnline(node) ? 'bg-green-400' : 'bg-white/30'"></div>
-              <span class="text-sm font-medium text-white truncate">{{ node.name || shortDid(node.did) }}</span>
+              <span class="text-sm font-medium text-white truncate" :title="node.did">{{ node.name || shortDid(node.did) }}</span>
               <span
                 class="text-xs shrink-0"
                 :class="nodeTransportIcon(node.did).color"