Introduces Docker deployment files (.dockerignore, Dockerfile, docker-compose.yml, docker-setup.sh, requirements-webui.txt, and README-Docker.md) for SoulSync WebUI. Refactors core/database_update_worker.py and core/media_scan_manager.py to support headless operation without PyQt6, enabling signal/callback compatibility for both GUI and non-GUI environments. Removes logs/app.log file.
This is needed if users manually correct failed matches on plex when songs are scanned in. If a db sync is done after the scan but before the manual modification,
