fix: address code review feedback

- SettingsView: replace broken Toggle+constant with a Button that directly
  opens system notification settings (Toggle was bound to .constant(true)
  and onChange never fired)
- HTTPClient: append query parameters to URL for GET requests instead of
  putting them in the request body (body is ignored for GET)
- PushNotificationService: document why info-severity alerts skip Live Activities
- NotificationsViewModel: document polling page-reset behavior

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Mayday/ViewModels/NotificationsViewModel.swift

@@ -70,6 +70,8 @@ class NotificationsViewModel: ObservableObject {
     }
 
     func startPolling() {
+        // Polling always reloads page 1 to pick up new notifications.
+        // Users who have scrolled to older pages will have the list reset on each interval.
         pollingTask = Task {
             while !Task.isCancelled {
                 try? await Task.sleep(for: .seconds(30))