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/Services/PushNotificationService.swift

@@ -76,6 +76,8 @@ class PushNotificationService: NSObject, ObservableObject, UNUserNotificationCen
               let severityStr = attributes["severity"] as? String,
               let severity = Severity(rawValue: severityStr) else { return }
 
+        // Info-level alerts don't warrant a persistent Live Activity — they are low-priority
+        // and should only appear as a standard banner notification.
         guard severity != .info else { return }
 
         // Limit to 3 concurrent activities