Sign-up guard: honeypot field renamed so browser autofill cannot trip it; log every guard rejection; clearer stale-page message

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

public/my.html

@@ -34,7 +34,7 @@
       <p class="muted small">Type your email and we send a 6-digit code. No password to invent,
         no password to forget. New emails get a free account automatically.</p>
       <p><input id="mcEmail" type="email" placeholder="Email" autocomplete="email" style="width:100%"></p>
-      <input id="mcWebsite" class="hp-field" type="text" name="website" tabindex="-1" autocomplete="off" aria-hidden="true">
+      <input id="mcWebsite" class="hp-field" type="text" name="hp_field_x9" tabindex="-1" autocomplete="off" aria-hidden="true">
       <div id="mcCheck" hidden></div>
       <p id="mcCodeRow" hidden><input id="mcCode" inputmode="numeric" placeholder="6-digit code" style="width:100%"></p>
       <button class="btn" id="mcSendBtn">Email me a code</button>
@@ -899,7 +899,7 @@
     </div>
   </div>
 </div>
-<script src="/assets/common.js?v=20260911b"></script>
+<script src="/assets/common.js?v=20260911c"></script>
 <script src="/assets/wallet.js?v=20260911a"></script>
 <script src="/assets/promo.js?v=20260911a"></script>
 <script src="/assets/my.js?v=20260911v"></script>