chore(assets): replace lnd icon svg with png

lnd.svg no longer exists; every reference now points at lnd.png.

neode-ui/src/views/apps/appsConfig.ts

@@ -237,7 +237,7 @@ const APP_ICON_FALLBACKS: Record<string, string> = {
   'mysql-mempool': '/assets/img/app-icons/mempool.webp',
   // bitcoin / lightning companion UIs
   'archy-bitcoin-ui': '/assets/img/app-icons/bitcoin-knots.webp',
-  'archy-lnd-ui': '/assets/img/app-icons/lnd.svg',
+  'archy-lnd-ui': '/assets/img/app-icons/lnd.png',
   'archy-electrs-ui': '/assets/img/app-icons/electrumx.png',
   // ElectrumX ships under a few historical ids (the backend was renamed
   // electrs → electrumx). Without an explicit map, an `electrs`-keyed install