Show 25 most recent transactions from all addresses on home screen

Fetch transactions for every address across all wallets in parallel,
merge and deduplicate by hash, apply anti-poisoning filters, sort by
block number, and display the top 25 below the wallet list. Clicking
a transaction navigates to the address detail page for the relevant
address. Shows "Loading..." placeholder to prevent layout shift.

src/popup/index.html

@@ -217,6 +217,14 @@
                 <!-- wallet list -->
                 <div id="wallet-list"></div>
 
+                <!-- recent transactions across all addresses -->
+                <div class="border-t border-border mt-3 pt-2">
+                    <h3 class="font-bold text-xs mb-1">Recent Transactions</h3>
+                    <div id="home-tx-list">
+                        <div class="text-muted text-xs py-1">Loading...</div>
+                    </div>
+                </div>
+
                 <div class="text-xs text-muted mt-2">
                     <span
                         id="btn-add-wallet-bottom"