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/addressDetail.js

@@ -4,6 +4,8 @@ const {
     showFlash,
     balanceLinesForAddress,
     addressDotHtml,
+    escapeHtml,
+    formatAddressHtml,
     truncateMiddle,
 } = require("./helpers");
 const { state, currentAddress } = require("../../shared/state");
@@ -76,12 +78,6 @@ function timeAgo(timestamp) {
     return years + " year" + (years !== 1 ? "s" : "") + " ago";
 }
 
-function escapeHtml(s) {
-    const div = document.createElement("div");
-    div.textContent = s;
-    return div.innerHTML;
-}
-
 let loadedTxs = [];
 
 let ensNameMap = new Map();