Клиент: Rust-интерфейс и протокол RSX

Чекпойнт: Rust-меню, настройки, Play, пауза, ресурспаки, кейбинды, RSX-протокол, шрифты и иконки. Перед финальным пушем история будет разбита на логические коммиты.

docs/design-system.md

@@ -145,8 +145,22 @@ Geist (400, 500, 600) and Geist Mono (400), bundled under the SIL Open Font Lice
   stacks of panels, the stone texture behind the page and Horizon's pixel landscape (a dawn or a
   sunset) behind the hero. Light and dark follow the system, with a toggle. A giant wordmark in
   pixels sits in the footer.
-- **Game**: vanilla's screens. The on-screen keyboard is a rounded plate of keys in the page
-  colour, the focused key in the accent.
+- **Game**: vanilla's screens, except the main menu. `rustui`
+  (`horizon-client/src/rustui`) draws Horizon's Home in the Rust 2025 look: a veiled panorama
+  under charcoal plates with one Rust-orange accent, the top bar carrying the wordmark, the
+  tabs (ГЛАВНАЯ, ИГРАТЬ, two locked `???` chips that explain themselves on hover) and the
+  actions, quick connect and the devblog card on the right, the chat strip and the account plate
+  along the bottom. Its palette is `rustui::theme`, WCAG-tested over the veil; panels paint
+  procedurally until a Figma export sits in the resource root as `gui/sprites/rustui/<name>`.
+  The menu lays out in dp (the launcher's 1040x700 frame scaled to the window) and hit-tests the
+  same layout it draws. `horizon.txt:rustMenu:false` restores vanilla's main menu. The settings
+  screens use the same language (`rustui::settings`): a category rail on the left, one row per
+  setting with its value, bar or button on the right, the hovered setting's explanation in a
+  panel, and a footer with the version, the credit (Horizon, the Rust client this is based on,
+  MIT) and the way back. Their rows are vanilla's own widgets, so every setting behaves as
+  before; the Graphics and pack screens keep vanilla's own layouts for now.
+  `horizon.txt:rustSettings:false` restores vanilla's options screens. The on-screen
+  keyboard is a rounded plate of keys in the page colour, the focused key in the accent.
 
 ## Blocks