fix: unify address display with shared renderAddressHtml utility

All address rendering now uses a single renderAddressHtml() function in
helpers.js that produces consistent output everywhere:
- Color dot (deterministic from address)
- Full address with dashed-underline click-to-copy affordance
- Etherscan external link icon

Refactored all callsites across 9 view files:
- approval.js: approvalAddressHtml now delegates to renderAddressHtml,
  added attachCopyHandlers for click-to-copy on approve-tx/sign/site views
- confirmTx.js: confirmAddressHtml uses renderAddressHtml, token contract
  address uses renderAddressHtml with attachCopyHandlers
- txStatus.js: toAddressHtml delegates to renderAddressHtml
- transactionDetail.js: txAddressHtml delegates to renderAddressHtml,
  decoded calldata addresses use renderAddressHtml
- home.js: active address display uses renderAddressHtml
- send.js: from-address display uses renderAddressHtml
- receive.js: address block uses formatAddressHtml (which delegates to
  renderAddressHtml), removed separate etherscan link element
- addressDetail.js: address line uses renderAddressHtml, export-privkey
  address uses renderAddressHtml
- addressToken.js: address line and contract info use renderAddressHtml

Also consolidated:
- EXT_ICON SVG constant moved to helpers.js (removed 6 duplicates)
- copyableHtml() moved to helpers.js (removed duplicate in transactionDetail)
- etherscanLinkHtml() moved to helpers.js (removed duplicates)
- attachCopyHandlers() moved to helpers.js (removed duplicate in txStatus)
- Removed unused local functions (etherscanTokenLink, etherscanAddressLink)
- Cleaned up unused imports across all files

closes #97

src/popup/views/approval.js

@@ -1,11 +1,12 @@
 const {
     $,
-    addressDotHtml,
     addressTitle,
     escapeHtml,
     showView,
     showError,
     hideError,
+    renderAddressHtml,
+    attachCopyHandlers,
 } = require("./helpers");
 const { state, saveState, currentNetwork } = require("../../shared/state");
 const { formatEther, formatUnits, Interface, toUtf8String } = require("ethers");
@@ -17,28 +18,11 @@ const uniswap = require("../../shared/uniswap");
 const runtime =
     typeof browser !== "undefined" ? browser.runtime : chrome.runtime;
 
-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>`;
-
 const erc20Iface = new Interface(ERC20_ABI);
 
 function approvalAddressHtml(address) {
-    const dot = addressDotHtml(address);
-    const link = `${currentNetwork().explorerUrl}/address/${address}`;
-    const extLink = `<a href="${link}" target="_blank" rel="noopener" class="inline-flex items-center">${EXT_ICON}</a>`;
     const title = addressTitle(address, state.wallets);
-    let html = "";
-    if (title) {
-        html += `<div class="flex items-center font-bold">${dot}${escapeHtml(title)}</div>`;
-        html += `<div class="break-all">${escapeHtml(address)}${extLink}</div>`;
-    } else {
-        html += `<div class="flex items-center">${dot}<span class="break-all">${escapeHtml(address)}</span>${extLink}</div>`;
-    }
-    return html;
+    return renderAddressHtml(address, { title });
 }
 
 function formatTxValue(val) {
@@ -53,10 +37,6 @@ function tokenLabel(address) {
     return t ? t.symbol : null;
 }
 
-function etherscanTokenLink(address) {
-    return `${currentNetwork().explorerUrl}/token/${address}`;
-}
-
 // Try to decode calldata using known ABIs.
 // Returns { name, description, details } or null.
 function decodeCalldata(data, toAddress) {
@@ -235,10 +215,6 @@ function showTxApproval(details) {
             toHtml += `<div class="font-bold mb-1">${escapeHtml(symbol)}</div>`;
         }
         toHtml += approvalAddressHtml(toAddr);
-        if (symbol) {
-            const link = etherscanTokenLink(toAddr);
-            toHtml = toHtml.replace("</div>", "") + ""; // approvalAddressHtml already has etherscan link
-        }
         $("approve-tx-to").innerHTML = toHtml;
     } else {
         $("approve-tx-to").innerHTML = escapeHtml("(contract creation)");
@@ -266,12 +242,9 @@ function showTxApproval(details) {
             detailsHtml += `<div class="text-muted">${escapeHtml(d.label)}</div>`;
             if (d.address) {
                 if (d.isToken) {
-                    const tLink = etherscanTokenLink(d.address);
                     detailsHtml += `<div class="font-bold">${escapeHtml(tokenLabel(d.address) || "Unknown token")}</div>`;
-                    detailsHtml += approvalAddressHtml(d.address);
-                } else {
-                    detailsHtml += approvalAddressHtml(d.address);
                 }
+                detailsHtml += approvalAddressHtml(d.address);
             } else {
                 detailsHtml += `<div class="font-bold">${escapeHtml(d.value)}</div>`;
             }
@@ -295,6 +268,7 @@ function showTxApproval(details) {
     hideError("approve-tx-error");
 
     showView("approve-tx");
+    attachCopyHandlers("view-approve-tx");
 }
 
 function decodeHexMessage(hex) {
@@ -392,6 +366,7 @@ function showSignApproval(details) {
     $("btn-approve-sign").classList.remove("text-muted");
 
     showView("approve-sign");
+    attachCopyHandlers("view-approve-sign");
 }
 
 function show(id) {
@@ -419,6 +394,7 @@ function show(id) {
         $("approve-address").innerHTML = approvalAddressHtml(
             state.activeAddress,
         );
+        attachCopyHandlers("view-approve-site");
         $("approve-remember").checked = state.rememberSiteChoice;
     });
 }