feat: make block number click-to-copy with Etherscan external link on success-tx view

Closes #99

The block number on the success-tx view is now styled consistently with
other blockchain entities (addresses, tx hashes): it has a dashed underline
for click-to-copy and an external link icon pointing to etherscan.io/block/.

src/popup/index.html

@@ -577,19 +577,6 @@
                     <div id="confirm-fee-amount" class="text-xs"></div>
                 </div>
                 <div id="confirm-warnings" class="mb-2 hidden"></div>
-                <div
-                    id="confirm-recipient-warning"
-                    class="mb-2"
-                    style="visibility: hidden"
-                >
-                    <div
-                        class="border border-red-500 border-dashed p-2 text-xs font-bold text-red-500"
-                    >
-                        WARNING: The recipient address has ZERO transaction
-                        history. This may indicate a fresh or unused address.
-                        Double-check the address before sending.
-                    </div>
-                </div>
                 <div
                     id="confirm-errors"
                     class="mb-2 border border-border border-dashed p-2 hidden"

src/popup/views/confirmTx.js

@@ -243,13 +243,7 @@ function show(txInfo) {
     state.viewData = { pendingTx: txInfo };
     showView("confirm-tx");
 
-    // Reset recipient warning: reserve space (visibility:hidden) while
-    // the async check runs, preventing layout shift per README policy.
-    const recipientWarning = $("confirm-recipient-warning");
-    recipientWarning.style.visibility = "hidden";
-
     estimateGas(txInfo);
-    checkRecipientHistory(txInfo);
 }
 
 async function estimateGas(txInfo) {
@@ -292,30 +286,6 @@ async function estimateGas(txInfo) {
     }
 }
 
-async function checkRecipientHistory(txInfo) {
-    const el = $("confirm-recipient-warning");
-    try {
-        const provider = getProvider(state.rpcUrl);
-        // Skip warning for contract addresses — they may legitimately
-        // have zero outgoing transactions (getTransactionCount returns
-        // the nonce, i.e. sent-tx count only).
-        const code = await provider.getCode(txInfo.to);
-        if (code && code !== "0x") {
-            // Contract address — no warning needed, keep space reserved
-            // but invisible to prevent layout shift
-            return;
-        }
-        const txCount = await provider.getTransactionCount(txInfo.to);
-        if (txCount === 0) {
-            el.style.visibility = "visible";
-        }
-        // If txCount > 0, leave visibility:hidden — space stays reserved
-    } catch (e) {
-        log.errorf("recipient history check failed:", e.message);
-        // On error, leave visibility:hidden — no layout shift, no false warning
-    }
-}
-
 function init(ctx) {
     $("btn-confirm-send").addEventListener("click", async () => {
         const password = $("confirm-tx-password").value;

src/popup/views/transactionDetail.js

@@ -158,9 +158,8 @@ function render() {
         loadCalldata(tx.hash, tx.to);
     }
 
-    const isoStr = isoDate(tx.timestamp);
-    $("tx-detail-time").innerHTML =
-        copyableHtml(isoStr) + " (" + escapeHtml(timeAgo(tx.timestamp)) + ")";
+    $("tx-detail-time").textContent =
+        isoDate(tx.timestamp) + " (" + timeAgo(tx.timestamp) + ")";
     $("tx-detail-status").textContent = tx.isError ? "Failed" : "Success";
     showView("transaction");