Minor UI improvements, state saving

Model/Channel.swift

@@ -0,0 +1,12 @@
+import AVFoundation
+import Defaults
+import Foundation
+
+struct Channel: Codable, Defaults.Serializable {
+    var id: String
+    var name: String
+
+    static func from(video: Video) -> Channel {
+        Channel(id: video.channelID, name: video.author)
+    }
+}