feature/lock screen layout indicator

[qqiwi92]

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Kooha-2026-07-30-22-37-27.webm

I have two languages on my system and when entering password, I am always wondering what the active keyboard layout is. So I decided to add a label showing selected language. I have to say that AI was used for searching the optimal solutions and best practices.
Also I've experienced this bug where the language popup was empty and for video demo i had to mock data like this (did not commit mocking):

  let mock_layouts = vec![
                common::ActiveLayout { layout: "us".to_string(), description: "English (US)".to_string(), variant: "".to_string() },
                common::ActiveLayout { layout: "ru".to_string(), description: "Russian".to_string() , variant: "".to_string()},
            ];

So I can't 100% say that this is tested as i could not make just mock get the languages. I also noticed that in locker.rs the same code is being used as in greeter.rs, I thought that this is out of scope of this pr, as there is no logic there, but I can refine that as well