feat: add click-to-copy on timestamps in all transaction list views

Adds click-to-copy (copies ISO date string) to timestamp displays in:
- home view (relative time ago)
- addressDetail view (relative time ago)
- addressToken view (relative time ago)
- transactionDetail view (full ISO date)

All timestamps now show dashed underline to indicate copyability,
matching the existing UX pattern for addresses, tx hashes, and
block numbers.

src/popup/views/transactionDetail.js

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