Notification settings (Push)

- [ ] General notification settings:
- Sound on/off.
- Vibration on/off.
- Select notification sound.

- [ ] Select accounts for notification.

- [ ] Select actions to be notified about:
- Place order.
- Fill order.
- Cancel order.
- Transfer.

The issue lists push-notification preferences for sound, vibration, notification sounds, accounts, and order actions, but names no files, tests, or entry points. First identify the existing notification and settings implementation and clarify the supported accounts and actions; done means each listed preference can be configured and controls the corresponding notifications.

Written by the indexing model from the issue text.