Fix PostgreSQL 18 volume mount for Paperless

- Change volume mount from /var/lib/postgresql/data to /var/lib/postgresql
- PostgreSQL 18+ requires single mount at /var/lib/postgresql for compatibility
- Fixes migration errors and database initialization issues
- Allows proper pg_upgrade usage without mount point boundary issues
- Reference: docker-library/postgres#1259

Verified:
- Database starts successfully with correct volume structure
- All Django migrations apply without errors
- Paperless webserver running on http://localhost:8000
- All 7 containers healthy (db, broker, minio, tika, gotenberg, minio-sync, webserver)

Author: marc4gov

paperless-ngx-dms/docker-compose.yml

@@ -13,7 +13,7 @@ services:
     ports:
       - "5433:5432" # Expose voor externe toegang (niet conflicteren met main project)
     volumes:
-      - pgdata:/var/lib/postgresql/data
+      - pgdata:/var/lib/postgresql
       - ./init-db:/docker-entrypoint-initdb.d
     environment:
       POSTGRES_DB: paperless