feat (ui): series overlay

app/templates/index.html

@@ -192,6 +192,26 @@
       </div>
     </div>
 
+    <div id="tvdbModal" class="modal hidden" aria-hidden="true">
+      <div class="modal-card tvdb-modal-card">
+        <div class="row modal-head tvdb-modal-head">
+          <h3>TVDB Preview</h3>
+          <div class="panel-head-actions">
+            <button id="tvdbModalOpenInTabBtn" class="secondary">Open in tab</button>
+            <button id="closeTvdbModalBtn" class="secondary" aria-label="Close TVDB preview">✕</button>
+          </div>
+        </div>
+        <p id="tvdbModalStatus" class="muted"></p>
+        <div id="tvdbModalFallback" class="tvdb-fallback hidden">
+          <h4>Embedding blocked or unavailable</h4>
+          <p>
+            This page cannot be embedded here. TheTVDB may block framing using browser security headers.
+          </p>
+        </div>
+        <iframe id="tvdbModalFrame" title="TVDB Preview" class="tvdb-modal-frame"></iframe>
+      </div>
+    </div>
+
     <script src="/static/app.js"></script>
   </body>
 </html>