Remove test privkey from demo display

Users can share the key out of band instead

Author: melvincarvalho

demo.html

@@ -352,8 +352,7 @@ <h1>📝 Live Notes</h1>
     <div id="keyPanel" class="key-panel">
       <label>Nostr Private Key (hex)</label>
       <input type="password" id="privkeyInput" placeholder="Enter your private key to enable editing..." oninput="onPrivkeyChange()">
-      <div class="hint">Your key is stored locally and used to sign commits and Nostr events.<br>
-      For testing: <code style="font-size:11px;color:#a78bfa;">07f689807708ca937e1fdbea750ea70802fdec379f890306f6dc4716d0798948</code></div>
+      <div class="hint">Your key is stored locally and used to sign commits and Nostr events.</div>
       <div id="pubkeyDisplay" class="pubkey"></div>
     </div>