Improve notification view filtering UX

- Add subtitle below the toolbar title to indicate the state of the filter
- Add settings icon to take user to the notification settings page, and
  thus make that more discoverable

Testing
-------

PASS

Device: iPhone 13 mini
iOS: 17.6.1
Coverage:
1. Switching back and forth between the notifications tab and other tabs
   causes subtitle to show/hide as expected in both filter options
   (all, friends)
2. Subtitle follows the friends filter
3. Subtitle shows after restarting the app
4. Settings icon appears and takes user to the notification setting view
5. Notification settings can be updated from that view.

Changelog-Changed: Improve notification view filtering UX
Closes: https://github.com/damus-io/damus/issues/2480
Signed-off-by: Daniel D’Aquino <daniel@daquino.me>

damus/Views/Notifications/NotificationsView.swift

@@ -56,6 +56,7 @@ struct NotificationsView: View {
     @ObservedObject var notifications: NotificationsModel
     @StateObject var filter = NotificationFilter()
     @SceneStorage("NotificationsView.filter_state") var filter_state: NotificationFilterState = .all
+    @Binding var subtitle: String?
     
     @Environment(\.colorScheme) var colorScheme
     
@@ -99,6 +100,15 @@ struct NotificationsView: View {
             .tag(NotificationFilterState.replies)
         }
         .toolbar {
+            ToolbarItem(placement: .navigationBarTrailing) {
+                Button(
+                    action: { state.nav.push(route: Route.NotificationSettings(settings: state.settings)) },
+                    label: {
+                        Image("settings")
+                            .foregroundColor(.gray)
+                    }
+                )
+            }
             ToolbarItem(placement: .navigationBarTrailing) {
                 if would_filter_non_friends_from_notifications(contacts: state.contacts, state: filter_state, items: self.notifications.notifications) {
                     FriendsButton(filter: $filter.fine_filter)
@@ -107,12 +117,14 @@ struct NotificationsView: View {
         }
         .onChange(of: filter.fine_filter) { val in
             state.settings.friend_filter = val
+            self.subtitle = filter.fine_filter.description()
         }
         .onChange(of: filter_state) { val in
             filter.state = val
         }
         .onAppear {
             self.filter.fine_filter = state.settings.friend_filter
+            self.subtitle = filter.fine_filter.description()
             filter.state = filter_state
         }
         .safeAreaInset(edge: .top, spacing: 0) {
@@ -163,7 +175,7 @@ struct NotificationsView: View {
 
 struct NotificationsView_Previews: PreviewProvider {
     static var previews: some View {
-        NotificationsView(state: test_damus_state, notifications: NotificationsModel(), filter: NotificationFilter())
+        NotificationsView(state: test_damus_state, notifications: NotificationsModel(), filter: NotificationFilter(), subtitle: .constant(nil))
     }
 }
 
@@ -174,7 +186,7 @@ func would_filter_non_friends_from_notifications(contacts: Contacts, state: Noti
             continue
         }
         
-        if item.would_filter({ ev in FriendFilter.friends.filter(contacts: contacts, pubkey: ev.pubkey) }) {
+        if item.would_filter({ ev in FriendFilter.friends_of_friends.filter(contacts: contacts, pubkey: ev.pubkey) }) {
             return true
         }
     }