Fix sidebar links: use Tailscale IP when accessed via public domain

dashboard/frontend/src/components/Sidebar.svelte

@@ -9,6 +9,7 @@
   ];
 
   const LAN_IP = "192.168.31.221";
+  const TS_IP = "100.78.131.124";
   let lanReachable = $state(false);
 
   if (typeof window !== "undefined" && location.hostname !== LAN_IP) {
@@ -36,7 +37,10 @@
   function extHref(svc) {
     if (lanReachable && svc.port) return `http://${LAN_IP}:${svc.port}`;
     if (svc.remoteHref) return svc.remoteHref;
-    if (svc.port) return `${location.protocol}//${location.hostname}:${svc.port}`;
+    if (svc.port) {
+      const host = /^\d+\.\d+\.\d+\.\d+$/.test(location.hostname) ? location.hostname : TS_IP;
+      return `http://${host}:${svc.port}`;
+    }
     return svc.href;
   }