Adds Tidal as a third download source alongside Soulseek and YouTube. Uses the tidalapi library with device-flow authentication to search and download tracks in configurable quality (Low/High/Lossless/HiRes) with automatic fallback. Integrates into the download orchestrator for all modes (Tidal Only, Hybrid with fallback chain), the transfer monitor, post-processing pipeline, and file finder. Frontend includes download settings with quality selector, device auth flow, and dynamic sidebar/dashboard labels that reflect the active download source. No breaking changes for existing users.
