Integrated the RecordingView feature into the ContentView view in the Sample app target.

Apps/Attendi/AttendiApp.swift

@@ -1,10 +1,16 @@
 import SwiftUI
 
+/// The entry point of the Attendi sample app.
 @main
 struct AttendiApp: App {
+
+    // MARK: Body
+
+    /// The content of the app: a single window group showing the ``ContentView``.
     var body: some Scene {
         WindowGroup {
             ContentView()
         }
     }
+    
 }