Function save_activated_window 

pub fn save_activated_window(
    origin_window_id: Option<&str>,
    new_window_id: &str,
)

Saves MRU state when activating a window.

Uses file locking to prevent race conditions during read-modify-write. Origin window becomes “previous”, and new window becomes “current”.

Arguments

• origin_window_id - The window the user was on when they started the launcher (window of origin)
• new_window_id - The window being activated