[Bug]: Notifications not working on macOS, versions 6.3.0 and 6.2.3, works in 6.2.2

### Checks before filing an issue

- [x] This issue doesn't reproduce on web browsers (such as in Chrome). If it does, [issue reports go to the Mattermost Server repository](https://github.com/mattermost/mattermost-server/issues).
- [x] I have checked the [issue tracker](https://github.com/mattermost/desktop/issues) and have not found an issue that matches the one I'm filing. This should include closed issues.
- [x] This issue is not a troubleshooting question. Troubleshooting questions go here: https://forum.mattermost.com/c/trouble-shoot/16.
- [x] This issue is not a feature request. You can request features and make product suggestions here: https://mattermost.com/suggestions/.
- [x] This issue reproduces on the most recent [stable version](https://github.com/mattermost/desktop/releases/latest), or the most recent [prerelease version](https://github.com/mattermost/desktop/releases) of the Mattermost Desktop App.
- [x] I have read the [contribution guidelines](https://github.com/mattermost/desktop/blob/master/CONTRIBUTING.md).

### Mattermost Desktop Version

6.3.0 / 6.2.3

### Operating System

macOS Tahoe 26.6.2

### Mattermost Server Version

11.10.1

### Steps to reproduce

send direct message to another user

### Expected behavior

notification received, app badge with unread count

### Observed behavior

no notification, no badge, no sound, macOS notifications activated in settings, focus mode off

### Log Output

```shell
I enabled debug logs, but nothing shows in logs, just silent.
```

### Additional Information

There was a recent issue #3852 , but it does not seem related, nothing like in that issue shows up in logs.

No source files or tests are named. Start by reproducing the missing notification, badge, and sound behavior on macOS 26.6.2 with Mattermost Desktop 6.3.0 or 6.2.3, then compare it with 6.2.2 and inspect the desktop notification path. Done means direct messages produce the expected notification, unread badge, and sound.

Written by the indexing model from the issue text.