Add stems_link support for Pingvin-Share-X delivery

templates/admin/request.html

@@ -178,6 +178,20 @@
             </div>
           </form>
         </div>
+
+        <!-- Stems / Extras Link -->
+        <div class="section">
+          <h2>Stems / Extras Link</h2>
+          <p class="copy-hint">Paste a self-hosted file share link (e.g. from Pingvin Share). It will appear on the customer player page once delivered.</p>
+          <form method="POST">
+            <input type="hidden" name="action" value="save_stems_link">
+            <label for="stems_link">Share link</label>
+            <input type="url" id="stems_link" name="stems_link" value="{{ req.stems_link or '' }}" placeholder="https://files.dionysismedia.ca/share/...">
+            <div class="actions">
+              <button type="submit" class="secondary">Save Link</button>
+            </div>
+          </form>
+        </div>
       </div>
 
       <!-- RIGHT COLUMN -->