refactor(backend): alihkan Settings ke zesdex-cms JsonSettingsRepository

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

crates/zesdex-backend/src/app/mode/settings.rs

@@ -3,7 +3,7 @@
 //! Flow: exposes small mutation functions (currently just cycling the
 //! internet access mode) invoked by keybindings while the settings overlay
 //! is active.
-use crate::model::settings::{InternetMode, Settings};
+use zesdex_cms::domain::settings::{InternetMode, Settings};
 
 /// Advance the internet access mode to the next value in the cycle.
 ///