after loading session, the main view is closeable

### What happened?

Normally you cannot close the first tab.

### Browsers

_No response_

### Operating systems

_No response_

### SNIK Graph version

SNIK Graph version 25.01
commit date 2025-08-13T08:44:49+02:00
ci(deps): bump actions/checkout from 4 to 5

### Relevant console output

```shell

```