[Bug Report] opensnitch-ui crash

### Describe the bug:

Since the last system update the opensnitch-ui began crashing whenever a network access would trigger the opensnitch-ui popup. It is reproducible with every new network request.

Include the following information:
- OpenSnitch version: `app-admin/opensnitch-1.8.0-r1`
- OS: Gentoo
- OS version: stable, with some unstable packages
- Window Manager: Sway
- Kernel version: 7.1.8

### To Reproduce:

Steps to reproduce the behavior:
1. Launch opensnitch-ui
2. Perform a network request that hasn't been allowed yet
3. See error

### Post error logs:

```
Loaded network aliases from /usr/lib/python3.14/site-packages/opensnitch/utils/network_aliases/network_aliases.json
qt.sql.qsqldatabase: QSqlDatabase requires a QCoreApplication
qt.sql.qsqldatabase: QSqlDatabase requires a QCoreApplication
qt.sql.qsqldatabase: QSqlDatabase requires a QCoreApplication
qt.sql.qsqldatabase: QSqlDatabase requires a QCoreApplication
~ OpenSnitch GUI - 1.8.0 ~
protobuf: 7.35.1 - grpc: 1.83.0
--------------------------------------------------

QT_AUTO_SCREEN_SCALE_FACTOR: True
QT_QPA_PLATFORM: wayland
gRPC Max Message Length: 4MiB
Bytes: 4194304
[server] addr: unix:///tmp/osui.sock
is new file, or IN MEMORY, setting initial schema version
setting schema version to: 3
setting schema version to: 3
Setting journal_mode: OFF
Setting DB memory optimizations
schema version: 3
db schema is up to date
actions.__init__ exception: [Errno 17] File exists: '/home/mrus/.config//opensnitch/actions/'
actions.__init__ exception: [Errno 17] File exists: '/home/mrus/.config//opensnitch/actions/'
Loading translations: /usr/lib/python3.14/site-packages/opensnitch/utils/../i18n locale: en_US
using IPASN DB: /home/mrus/.config/opensnitch/ipasn_db.dat.gz
exception loading ipasn db: [Errno 2] No such file or directory: '/usr/lib/python3/dist-packages/data/asnames.json'
Install python3-pyasn to display IP's network name.
actions.__init__ exception: [Errno 17] File exists: '/home/mrus/.config//opensnitch/actions/'
[server] using address: unix:///tmp/osui.sock auth type: simple
2026-08-19 18:07:48.149653 [Subscribe] unix:
Setting daemon DefaultAction to: deny
2026-08-19 18:07:48.165411 [Notifications] channel started: unix:

new node connected, listening for client responses... /local
[Nodes]: reply notification not in the list: 0
Traceback (most recent call last):
File "/usr/lib/python3.14/site-packages/opensnitch/dialogs/prompt/__init__.py", line 227, in _check_advanced_toggled
self.move_popup()
~~~~~~~~~~~~~~~^^
File "/usr/lib/python3.14/site-packages/opensnitch/dialogs/prompt/__init__.py", line 193, in move_popup
point = self.screen().virtualSiblingAt(QtGui.QCursor.pos()).availableGeometry()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'availableGeometry'
[1] 16973 IOT instruction opensnitch-ui
```

Start with opensnitch/dialogs/prompt/__init__.py, especially move_popup at the traceback location, and reproduce the crash by triggering a new network request under Sway. Inspect why the screen lookup produces no geometry in this environment. Done means the prompt appears without crashing and the relevant reproduction no longer raises the reported AttributeError.

Written by the indexing model from the issue text.