feat: fix playlist limit, add folder sync option, and refactor client

[Oduanir]

Playlist Improvements: Pagination, Folder Organization & Stability Fixes

Description

This PR addresses stability issue regarding playlist handling, and introduces a new configuration option for file organization.

The primary goal was to resolve the 100-track limit on playlist downloads by properly paginating API requests. Additionally, a new feature allows users to force downloads into a dedicated playlist folder, bypassing the standard Artist/Album structure.

Changes

1. Feature: Standalone Playlist Folders

• Added a "Download tracks to playlist folder" option in the Monitor/Sync modal.
• Behavior: When enabled, tracks are downloaded directly into tidaloader_playlists/{PlaylistName}/.
• Scope: Applies to all Monitored Playlists (Tidal & ListenBrainz).
• Context: This allows users to keep playlist files self-contained. Note that this may result in file duplication if the tracks already exist in the main library, which is the intended behavior for this specific mode.

2. Fix: 100-Track Limit

• ADDRESSED: Issue where only the first 100 tracks of a playlist were retrieved.
• IMPLEMENTATION: Added pagination logic in get_playlist_tracks to iteratively fetch all available tracks (with a safety cap at 10,000).

3. Fix: Settings Attribute Error

• ADDRESSED: AttributeError: group_compilations causing manual sync tasks to fail.
• IMPLEMENTATION: Added the missing default group_compilations attribute to the Settings model in backend/api/settings.py.

4. Code Refactor

• Refactored backend/tidal_client.py to simplify the get_playlist_tracks method.
• Reduced cyclomatic complexity and improved readability of the pagination loop and response extraction logic.

How to Test

1. Sync Fix: Trigger a manual sync on an existing playlist to verify the process no longer crashes.
2. Pagination: Add a playlist containing more than 100 tracks and verify that the total track count is correct in the UI and that all files are queued/downloaded.
3. Folder Feature:
   • Add a new playlist to monitor (Tidal or ListenBrainz).
   • Check the "Download tracks to playlist folder" option.
   • Verify that files are downloaded into downloads/tidaloader_playlists/{PlaylistName}/ as a flat list, alongside the .m3u8 and cover image.

Type of Change

• Bug fix
• New feature
• Refactoring

[RayZ3R0]

Great PR, thanks!