NE Hub: Seafile, OnlyOffice, Plex, calendar and mail in one PWA

- Mobile-first PWA (phone tab bar with More menu, iPad/desktop rail)
- Passkey (WebAuthn) sign-in gates the whole app; first passkey via setup code
- Files: Seafile browse/upload/new doc/rename/move/share link/preview/delete
- In-app OnlyOffice editing with JWT-signed configs and save-back to Seafile
- Plex music player via plex.tv sign-in and a server-side proxy
- Calendar agenda from private ICS links (recurrence + time zones)
- Search, Home dashboard, webmail deep links, audiobooks frame
- Dockerfile, compose, and a Gitea Actions workflow that builds the image

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

docker-compose.yml

@@ -0,0 +1,12 @@
+services:
+  hub:
+    image: git.necloud.us/nate/hub:latest   # built by the Gitea workflow; `docker compose build` builds locally instead
+    build: .
+    restart: unless-stopped
+    ports:
+      - "8080:8080"
+    env_file: .env
+    volumes:
+      - hub-data:/data   # passkeys + session secret live here
+volumes:
+  hub-data: