Ensure disk device path has /dev/ prefix

iridium_installer/ui/pages/storage.py

@@ -89,8 +89,13 @@ class StoragePage(Adw.Bin):
 
     def on_disk_toggled(self, button, device_name):
         if button.get_active():
-            self.selected_disk = device_name
-            self.emit("disk-selected", device_name)
+            # Prepend /dev/ if it's just the name
+            full_path = device_name
+            if not device_name.startswith("/dev/"):
+                full_path = f"/dev/{device_name}"
+            
+            self.selected_disk = full_path
+            self.emit("disk-selected", full_path)
 
     def get_selected_disk(self):
         return self.selected_disk