fix: player connectivity and media download pipeline

- nginx: add /api/ shortcut block (no portal auth, X-Script-Name /digiserver,
  Host $http_host) so players can reach DigiServer API without /digiserver prefix
- nginx: use $http_host in /api/ block so Flask host_url includes port — fixes
  media download URLs missing :8080 (was http://ip/digiserver/... not http://ip:8080/...)
- player main.py: fix double-port bug when server_ip already contains a port
  (e.g. 192.168.0.230:8080 was producing http://192.168.0.230:8080:80)
- get_playlists_v2.py: force re-sync when server version differs OR local media
  files are missing on disk — fixes stale playlist after server reset
- digiserver api.py: playlist endpoint builds full media URLs using script_root
  from X-Script-Name header set by nginx
- weblink support, player build/deploy improvements, manage-playlist AJAX prefix fix

digiserver-v2/app/templates/admin/admin.html

@@ -116,6 +116,17 @@
             </a>
         </div>
     </div>
+
+    <!-- Build Player Files Card (Admin Only) -->
+    <div class="card management-card" style="background: linear-gradient(135deg, #0ba360 0%, #3cba92 100%);">
+        <h2>🧰 Build Player Files</h2>
+        <p>Pull the latest player code and bake its server config for deployment</p>
+        <div class="card-actions">
+            <a href="{{ url_for('admin.build_player') }}" class="btn btn-primary">
+                Build Player Files
+            </a>
+        </div>
+    </div>
     {% endif %}
 
     <!-- Quick Actions Card -->