Add Dashboard theme.

Jellyfin.Data/Entities/DisplayPreferences.cs

@@ -26,6 +26,7 @@ namespace Jellyfin.Data.Entities
             SkipBackwardLength = 10000;
             ScrollDirection = ScrollDirection.Horizontal;
             ChromecastVersion = ChromecastVersion.Stable;
+            DashboardTheme = string.Empty;
 
             HomeSections = new HashSet<HomeSection>();
         }
@@ -126,6 +127,13 @@ namespace Jellyfin.Data.Entities
         /// </remarks>
         public bool EnableNextVideoInfoOverlay { get; set; }
 
+        /// <summary>
+        /// Gets or sets the dashboard theme.
+        /// </summary>
+        [MaxLength(32)]
+        [StringLength(32)]
+        public string DashboardTheme { get; set; }
+
         /// <summary>
         /// Gets or sets the home sections.
         /// </summary>

MediaBrowser.Api/DisplayPreferencesService.cs

@@ -144,6 +144,7 @@ namespace MediaBrowser.Api
                 : true;
             prefs.SkipBackwardLength = request.CustomPrefs.TryGetValue("skipBackLength", out var skipBackLength) ? int.Parse(skipBackLength) : 10000;
             prefs.SkipForwardLength = request.CustomPrefs.TryGetValue("skipForwardLength", out var skipForwardLength) ? int.Parse(skipForwardLength) : 30000;
+            prefs.DashboardTheme = request.CustomPrefs.TryGetValue("dashboardTheme", out var theme) ? theme : string.Empty;
             prefs.HomeSections.Clear();
 
             foreach (var key in request.CustomPrefs.Keys.Where(key => key.StartsWith("homesection")))