refactor: organize services by provider and standardize settings pattern

octo-fiesta/Models/DeezerSettings.cs

@@ -0,0 +1,25 @@
+namespace octo_fiesta.Models;
+
+/// <summary>
+/// Configuration for the Deezer downloader and metadata service
+/// </summary>
+public class DeezerSettings
+{
+    /// <summary>
+    /// Deezer ARL token (required for downloading)
+    /// Obtained from browser cookies after logging into deezer.com
+    /// </summary>
+    public string? Arl { get; set; }
+    
+    /// <summary>
+    /// Fallback ARL token (optional)
+    /// Used if the primary ARL token fails
+    /// </summary>
+    public string? ArlFallback { get; set; }
+    
+    /// <summary>
+    /// Preferred audio quality: FLAC, MP3_320, MP3_128
+    /// If not specified or unavailable, the highest available quality will be used.
+    /// </summary>
+    public string? Quality { get; set; }
+}