feat(stack): add Paperless-ngx document management system

- Add paperless.yml stack (port 8091, documents.schweitz.net)
- Uses shared postgres (DB: paperless) and redis (DB 8)
- ClamAV installed on host for virus scanning (port 3310)
- Add Paperless integration to library-desk stack
- Update CONTAINERS.md with Paperless and ClamAV profiles
- Add Portainer and NPM API documentation to setup-new-host.md
- Update redis-shared.yml and postgres-shared.yml with Paperless refs

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

stacks/redis-shared.yml

@@ -63,11 +63,16 @@ networks:
 #
 # Redis supports 16 databases (0-15). Assign one per application:
 #
-#   DB 0: General cache (default, shared lightweight caching)
-#   DB 1: Authentik (sessions, cache, message queue)
-#   DB 2: Gitea (cache, sessions)
-#   DB 3: Nextcloud (file locking, distributed cache, sessions)
-#   DB 4-15: Reserved for future applications
+#   DB 0: Authentik (sessions, cache, message queue)
+#   DB 1: Tatlock (memory)
+#   DB 2: Wiki.js
+#   DB 3: Scheduler
+#   DB 4: Library Desk
+#   DB 5: SearXNG
+#   DB 6: Tatlock (benchmarks)
+#   DB 7: Nextcloud (file locking, distributed cache, sessions)
+#   DB 8: Paperless (task queue, cache)
+#   DB 9-15: Reserved for future applications
 #
 # Connection Examples:
 #