Parallelize address scanning and unify address display formatting

Scanning: check all gap-limit addresses in parallel per batch instead
of sequentially. For a wallet with 1 used address this reduces from
12 sequential RPC round-trips to 1 parallel batch + 1 small follow-up.

Display: add shared formatAddressHtml(address, ensName, maxLen) and
escapeHtml() to helpers.js. Use them in confirm-tx (was missing color
dot entirely) and approval view. Remove duplicate escapeHtml from
addressDetail.js.

src/popup/views/helpers.js

@@ -137,6 +137,27 @@ function addressDotHtml(address) {
     return `<span style="width:8px;height:8px;border-radius:50%;display:inline-block;background:${color};margin-right:4px;vertical-align:middle;flex-shrink:0;"></span>`;
 }
 
+function escapeHtml(s) {
+    const div = document.createElement("div");
+    div.textContent = s;
+    return div.innerHTML;
+}
+
+// Render an address with color dot, optional ENS name, optional truncation.
+// When ensName is provided, shows ENS name (bold) on one line and
+// the address below it. Otherwise shows just the dotted address.
+function formatAddressHtml(address, ensName, maxLen) {
+    const dot = addressDotHtml(address);
+    const displayAddr = maxLen ? truncateMiddle(address, maxLen) : address;
+    if (ensName) {
+        return (
+            `<div class="flex items-center font-bold">${dot}${escapeHtml(ensName)}</div>` +
+            `<div class="break-all">${escapeHtml(displayAddr)}</div>`
+        );
+    }
+    return `<div class="flex items-center">${dot}<span class="break-all">${escapeHtml(displayAddr)}</span></div>`;
+}
+
 module.exports = {
     $,
     showError,
@@ -146,5 +167,7 @@ module.exports = {
     balanceLinesForAddress,
     addressColor,
     addressDotHtml,
+    escapeHtml,
+    formatAddressHtml,
     truncateMiddle,
 };