Make active address display copyable with etherscan link

Click the active address above Send/Receive to copy it. A small
box-arrow icon links to the address on etherscan.

src/popup/views/home.js

@@ -4,6 +4,7 @@ const {
     showFlash,
     balanceLinesForAddress,
     addressDotHtml,
+    escapeHtml,
 } = require("./helpers");
 const { state, saveState, currentAddress } = require("../../shared/state");
 const { updateSendBalance, renderSendTokenSelect } = require("./send");
@@ -21,12 +22,27 @@ function renderTotalValue() {
     el.textContent = formatUsd(getTotalValueUsd(state.wallets));
 }
 
+const EXT_ICON =
+    `<span style="display:inline-block;width:10px;height:10px;margin-left:4px;vertical-align:middle">` +
+    `<svg viewBox="0 0 12 12" fill="none" stroke="currentColor" stroke-width="1.5">` +
+    `<path d="M4.5 1.5H2a.5.5 0 00-.5.5v8a.5.5 0 00.5.5h8a.5.5 0 00.5-.5V7.5"/>` +
+    `<path d="M7 1.5h3.5V5M7 5.5L10.5 1.5"/>` +
+    `</svg></span>`;
+
 function renderActiveAddress() {
     const el = $("active-address-display");
     if (!el) return;
     if (state.activeAddress) {
-        const dot = addressDotHtml(state.activeAddress);
-        el.innerHTML = dot + state.activeAddress;
+        const addr = state.activeAddress;
+        const dot = addressDotHtml(addr);
+        const link = `https://etherscan.io/address/${addr}`;
+        el.innerHTML =
+            `<span class="underline decoration-dashed cursor-pointer" id="active-addr-copy">${dot}${escapeHtml(addr)}</span>` +
+            `<a href="${link}" target="_blank" rel="noopener" class="inline-flex items-center">${EXT_ICON}</a>`;
+        $("active-addr-copy").addEventListener("click", () => {
+            navigator.clipboard.writeText(addr);
+            showFlash("Copied!");
+        });
     } else {
         el.textContent = "";
     }