feat: add Trailer Pre-Roll and Feature Pre-Roll bumpers

Adds two optional IIntroProvider bumper slots, mirroring CherryFloors'
cinema mode plugin: a "Trailer Pre-Roll" played before the trailer block
and a "Feature Pre-Roll" played right before the movie/episode. Each is
configured by picking an existing Jellyfin Movie library, from which a
random Movie is injected as the bumper.

Bump version to 1.0.0.5.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Jellyfin.Plugin.CinemaTrailers4Jellyfins/Configuration/PluginConfiguration.cs

@@ -68,5 +68,15 @@ namespace Jellyfin.Plugin.CinemaTrailers4Jellyfins.Configuration
 
         /// <summary>Also inject trailers before TV episodes, but only before the first episode a user watches each day.</summary>
         public bool TrailersForEpisodes { get; set; } = false;
+
+        // ── Pre-Roll Bumpers ─────────────────────────────────────────────────
+
+        /// <summary>Jellyfin movie library (VirtualFolder ItemId) to pick a random "Trailer Pre-Roll"
+        /// bumper from, played before the trailer block. Empty = disabled.</summary>
+        public string TrailerPreRollLibraryId { get; set; } = string.Empty;
+
+        /// <summary>Jellyfin movie library (VirtualFolder ItemId) to pick a random "Feature Pre-Roll"
+        /// bumper from, played after the trailer block, right before the feature. Empty = disabled.</summary>
+        public string FeaturePreRollLibraryId { get; set; } = string.Empty;
     }
 }