fix: say a contract creation has no recipient instead of a blank line (closes #250)

A transaction with no `to` showed a blank address, with a colour dot whose
colour was `undefined`, on the wait, success and error screens, the
transaction detail view and the history rows on Home, AddressDetail and
AddressToken. The approval screen showed "(contract creation)".

All of them now say "This transaction creates a new contract. It has no
recipient." The three history lists draw a row's counterparty lines through
one helper in helpers.js. A transaction with a real `to` is unchanged. The
new test drives each screen and list both ways.

Model: opus-5-5

src/popup/views/helpers.js

@@ -431,6 +431,29 @@ function addressTitle(address, wallets) {
     return null;
 }
 
+// What every recipient line and history row says for a transaction with no
+// `to`. Such a transaction creates a contract, so there is no address to show,
+// and a blank line on these screens reads as a rendering fault.
+const CONTRACT_CREATION_TEXT =
+    "This transaction creates a new contract. It has no recipient.";
+
+// The last two lines of a transaction history row: the counterparty's colour
+// dot and name beside the amount, then its full address. A contract creation
+// the user sent has no counterparty (its `to` is ""), so its row has the
+// amount alone and the contract creation sentence in place of the address.
+function txCounterpartyHtml(address, nameHtml, amountHtml) {
+    if (!address) {
+        return (
+            `<div class="flex justify-between"><span></span><span>${amountHtml}</span></div>` +
+            `<div>${escapeHtml(CONTRACT_CREATION_TEXT)}</div>`
+        );
+    }
+    return (
+        `<div class="flex justify-between"><span class="flex items-center">${addressDotHtml(address)}${nameHtml}</span><span>${amountHtml}</span></div>` +
+        `<div class="am-address">${escapeHtml(address)}</div>`
+    );
+}
+
 // Render an address with color dot, optional ENS name, optional title,
 // and optional truncation. Title and ENS are shown as bold labels above
 // the full address.
@@ -643,6 +666,8 @@ module.exports = {
     escapeHtml,
     displaySymbol,
     addressTitle,
+    CONTRACT_CREATION_TEXT,
+    txCounterpartyHtml,
     formatAddressHtml,
     renderAddressHtml,
     copyableHtml,