feat(demo): real registry UIs, IndeeHub iframe proxy, mempool tab, media Range

- App UIs now use the real registry shells with dummy data: bitcoin-ui for
  Bitcoin Core (Satoshi subversion) and Bitcoin Knots (Knots subversion) via
  per-path /app/bitcoin-{core,knots}/bitcoin-status; the real lnd-ui (mock
  /proxy/lnd/v1/getinfo+channels, /lnd-connect-info, /api/container/logs); the
  static fedimint-ui. ElectrumX already on the real electrs-ui. Custom mock UIs
  dropped — accurate UX.
- IndeeHub loads in the iframe: nginx reverse-proxies /app/indeedhub/ →
  indee.tx1138.com and strips X-Frame-Options/CSP (it blocked framing before).
- Mempool opens in a new tab (mempool.space can't be iframed).
- Cloud media playback: HTTP Range support in the curated-file server so audio/
  video can stream and seek (needs real files dropped into demo/files/).
- Dockerfile/.dockerignore copy docker/lnd-ui + docker/fedimint-ui.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

neode-ui/docker/nginx-demo.conf

@@ -70,6 +70,20 @@ http {
             proxy_set_header X-Real-IP $remote_addr;
         }
 
+        # LND UI endpoints (polled by the lnd-ui shell)
+        location /proxy/ {
+            proxy_pass http://neode-backend:5959;
+            proxy_http_version 1.1;
+            proxy_set_header Host $host;
+            proxy_set_header X-Real-IP $remote_addr;
+        }
+        location /lnd-connect-info {
+            proxy_pass http://neode-backend:5959;
+            proxy_http_version 1.1;
+            proxy_set_header Host $host;
+            proxy_set_header X-Real-IP $remote_addr;
+        }
+
         # Proxy FileBrowser API to mock backend (demo mode)
         location /app/filebrowser/ {
             client_max_body_size 10G;
@@ -80,6 +94,19 @@ http {
             proxy_request_buffering off;
         }
 
+        # IndeeHub: reverse-proxy the real site same-origin and strip its
+        # X-Frame-Options / CSP so it can load inside the in-app iframe.
+        location /app/indeedhub/ {
+            proxy_pass https://indee.tx1138.com/;
+            proxy_http_version 1.1;
+            proxy_set_header Host indee.tx1138.com;
+            proxy_ssl_server_name on;
+            proxy_set_header Accept-Encoding "";
+            proxy_hide_header X-Frame-Options;
+            proxy_hide_header Content-Security-Policy;
+            proxy_hide_header Content-Security-Policy-Report-Only;
+        }
+
         # Proxy every other app UI (/app/<id>/) to the mock backend, which serves
         # the per-app mock UIs (bitcoin-ui, electrumx, lnd, fedimint) and the
         # generic "Not available in the demo" notice for the rest.