Session directories are now created only when the first MP3 file is saved, not at session creation. Added EnsureSessionDirectoryExists to ISessionService and SessionService to handle this logic. Updated VideoService to call this method before saving files. Cleanup now logs when no directory exists for expired sessions.
Organize downloaded files into per-job subdirectories under "downloads" instead of a flat structure. Update DownloadController and VideoService to read, write, and delete files within these job-specific directories. Add helper methods for directory management and improve logging. Update download/delete endpoints and result URLs to reflect the new structure. Clean up empty job directories after file deletion.
Michal Vrba