add server url row and live verification check in invoice

index.html

@@ -156,6 +156,8 @@ tbody tr:hover{background:color-mix(in srgb,var(--accent-soft) 50%,transparent)}
 #qrcode img{width:160px;height:160px}
 .ok-line{color:var(--ok);font-weight:600;font-size:14px;margin-bottom:14px}
 .err-line{color:#d32f2f;font-weight:600;font-size:14px;margin-bottom:14px}
+.flag-ok{color:var(--ok);font-weight:600;font-size:13px}
+.flag-err{color:#d32f2f;font-weight:600;font-size:13px}
 
 .intro-card{
   background:var(--panel);border:1px solid var(--line);
@@ -287,6 +289,7 @@ footer a{color:var(--accent);text-decoration:none}
           <div class="row"><span>Address</span><span id="iv-addr">—</span></div>
           <div class="row"><span>Balance</span><span id="iv-balance">—</span></div>
           <div class="row"><span>Status</span><span id="iv-status2">—</span></div>
+          <div class="row"><span>Server</span><span><span id="iv-url">—</span> <span id="iv-url-check"></span></span></div>
           <div id="qrcode"></div>
         </div>
 
@@ -433,6 +436,26 @@ async function fetchData() {
   }
 }
 
+async function checkServer(url, chain) {
+  const flag = document.getElementById('iv-url-check');
+  flag.textContent = 'checking…';
+  flag.className = '';
+  try {
+    const r = await fetch(url + '/' + chain + '/info');
+    const data = await r.json();
+    if (data && data.address && data.base_fee != null) {
+      flag.textContent = '✓ verified';
+      flag.className = 'flag-ok';
+    } else {
+      flag.textContent = '✗ error';
+      flag.className = 'flag-err';
+    }
+  } catch (err) {
+    flag.textContent = '✗ error';
+    flag.className = 'flag-err';
+  }
+}
+
 document.getElementById('onion').addEventListener('change', e => {
   withTor = e.target.checked;
   fetchData();
@@ -468,6 +491,9 @@ document.getElementById('submit').addEventListener('click', async () => {
   document.getElementById('iv-addr').textContent = '—';
   document.getElementById('iv-balance').textContent = '—';
   document.getElementById('iv-status2').textContent = '—';
+  document.getElementById('iv-url').textContent = '—';
+  document.getElementById('iv-url-check').textContent = '';
+  document.getElementById('iv-url-check').className = '';
   document.getElementById('qrcode').innerHTML = '';
   const chain = getChain();
   try {
@@ -495,6 +521,9 @@ document.getElementById('submit').addEventListener('click', async () => {
     new QRCode(qrEl, invoiceuri);
     inv.classList.add('show');
     inv.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
+    const serverUrl = result.url || url;
+    document.getElementById('iv-url').textContent = serverUrl;
+    checkServer(serverUrl, result.chain || chain);
   } catch (err) {
     document.getElementById('iv-status').className = 'err-line';
     document.getElementById('iv-status').textContent = 'Network error. Please try again.';