fix: destroy solaar-keyboard uinput device when no receiver is connected

When a Logitech receiver is disconnected, tear down the uinput device
so GNOME/mutter no longer detects a virtual pointer, allowing touch
mode and the on-screen keyboard to activate correctly.

lib/logitech_receiver/diversion.py

@@ -268,6 +268,20 @@ def setup_uinput():
         logger.warning("cannot create uinput device: %s", e)
 
 
+def teardown_uinput():
+    global udevice
+    if udevice is None:
+        return
+    try:
+        udevice.close()
+        if logger.isEnabledFor(logging.INFO):
+            logger.info("uinput device closed")
+    except Exception as e:
+        logger.warning("cannot close uinput device: %s", e)
+    finally:
+        udevice = None
+
+
 def kbdgroup():
     if xkb_setup():
         state = XkbStateRec()

lib/solaar/ui/__init__.py

@@ -23,6 +23,7 @@ from typing import Callable
 import gi
 import yaml
 
+from logitech_receiver import diversion
 from logitech_receiver.common import Alert
 
 from solaar.i18n import _
@@ -130,6 +131,8 @@ def _status_changed(device, alert, reason, refresh=False):
         alert = Alert.NONE
 
     tray.update(device)
+    if device.kind is None and not tray._devices_info:
+        diversion.teardown_uinput()
     if alert & Alert.ATTENTION:
         tray.attention(reason)