Index: src/views/pages/paid-result.ejs
===================================================================
--- src/views/pages/paid-result.ejs	(revision 9019a3e8f59ad6d0b916a68ee153559d27f8c0e8)
+++ src/views/pages/paid-result.ejs	(revision ec288dc84c580f311e1c6cd5900dbd67738f7f62)
@@ -34,4 +34,8 @@
       <% } %>
     </div>
+
+    <% if (typeof debug !== 'undefined' && debug) { %>
+      <p class="pr-diag">diagnose: <code><%= debug %></code></p>
+    <% } %>
   </div>
 </section>
@@ -46,3 +50,5 @@
   .pr-btn { display: inline-block; padding: 11px 20px; border-radius: 10px; background: var(--accent,#6b8f71); color: #fff; text-decoration: none; font-weight: 600; }
   .pr-btn-ghost { background: transparent; color: var(--ink,#222); border: 1px solid color-mix(in srgb, var(--ink,#000) 22%, transparent); }
+  .pr-diag { margin: 18px 0 0; font-size: 12px; opacity: .6; word-break: break-all; }
+  .pr-diag code { font-family: ui-monospace, monospace; }
 </style>