Swap Nym mixnet references to Tor

The wallet's transport moved from the Nym mixnet to embedded Tor (Nym's
free-tier bandwidth is being removed upstream and the paid path needs a
token — not a foundation for a payments wallet). Update the marketing
copy and privacy policy to match: the "Mixnet, built in" feature card is
now about Tor, the payment-rail diagram and hero copy no longer claim a
5-hop mixnet, and nym.com links point to torproject.org instead.

privacy.html

@@ -38,9 +38,9 @@
       <li>Your seed, keys, contacts, payment history, and settings are stored
       <strong>only on your device</strong>. They are never uploaded.</li>
       <li>Wallet network traffic — relay connections, name lookups, exchange
-      rates — is routed through the Nym mixnet. The services you reach see
-      mixnet exit traffic, not your IP address, and the mixnet's 5-hop design
-      hides who is talking to whom at the network layer.</li>
+      rates — is routed through Tor. The services you reach see Tor exit
+      traffic, not your IP address. Tor hides your IP from the relay; the
+      relay and encryption handle the rest — content, sender, and timing.</li>
       <li>Payments travel as end-to-end encrypted nostr events. Relays see
       ciphertext and the recipient's ephemeral routing key — not the amount,
       the sender, or the message.</li>
@@ -64,8 +64,8 @@
       <li>Registration and release requests are authenticated by signature
       (<a href="https://nips.nostr.com/98" rel="noopener">NIP-98</a>); we never see a private key.</li>
       <li>Rate-limiting uses connection IP addresses transiently. Since the
-      wallet talks to goblin.st over the Nym mixnet, we typically see mixnet
-      exit addresses, not yours.</li>
+      wallet talks to goblin.st over Tor, we typically see a Tor exit
+      address, not yours.</li>
       <li>Release your name and it leaves public resolution immediately and
       becomes available for anyone to register.</li>
     </ul>