feat(ui): Ark wallet tab, balances, history badge + demo mocks

Ark tab in Wallet Settings (status, balances, receive address,
board/offboard, server config via wallet.ark-*), teal Ark badge in the
transactions modal, Ark row on the home wallet card (hidden until barkd
reports a balance), official bark icon, and wallet.ark-* mocks so the
public demo renders the tab.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

neode-ui/src/components/TransactionsModal.vue

@@ -52,7 +52,7 @@
                   <span
                     v-else
                     class="text-[10px] px-1.5 py-0.5 rounded-full font-medium"
-                    :class="tx.kind === 'lightning' ? 'bg-yellow-500/15 text-yellow-400' : tx.kind === 'cashu' ? 'bg-purple-500/15 text-purple-400' : 'bg-blue-500/15 text-blue-400'"
+                    :class="tx.kind === 'lightning' ? 'bg-yellow-500/15 text-yellow-400' : tx.kind === 'cashu' ? 'bg-purple-500/15 text-purple-400' : tx.kind === 'ark' ? 'bg-teal-500/15 text-teal-400' : 'bg-blue-500/15 text-blue-400'"
                   >
                     {{ kindLabel(tx) }}
                   </span>
@@ -90,7 +90,7 @@ interface WalletTransaction {
   label: string
   block_height: number
   // Which rail the transaction happened on; absent = onchain (older backends)
-  kind?: 'onchain' | 'lightning' | 'cashu' | 'fedimint'
+  kind?: 'onchain' | 'lightning' | 'cashu' | 'fedimint' | 'ark'
 }
 
 defineProps<{
@@ -114,6 +114,7 @@ function kindLabel(tx: WalletTransaction): string {
   if (tx.kind === 'lightning') return '⚡ Lightning'
   if (tx.kind === 'cashu') return 'Cashu'
   if (tx.kind === 'fedimint') return 'Fedimint'
+  if (tx.kind === 'ark') return 'Ark'
   return ''
 }