Add share actions to video context menu

Model/NavigationModel.swift

@@ -66,6 +66,9 @@ final class NavigationModel: ObservableObject {
     @Published var presentingSettings = false
     @Published var presentingWelcomeScreen = false
 
+    @Published var presentingShareSheet = false
+    @Published var shareURL: URL?
+
     @Published var alert = Alert(title: Text("Error"))
     @Published var presentingAlert = false
     #if os(macOS)
@@ -205,6 +208,11 @@ final class NavigationModel: ObservableObject {
         alert = Alert(title: Text(title), message: Text(message))
         presentingAlert = true
     }
+
+    func presentShareSheet(_ url: URL) {
+        shareURL = url
+        presentingShareSheet = true
+    }
 }
 
 typealias TabSelection = NavigationModel.TabSelection