Architecture

Grid Screen separates the Svelte webview from a Rust application core.

Svelte components and stores
  -> src/lib/commands.ts Tauri IPC wrapper
  -> src-tauri/src/app_shell.rs command handlers
  -> shared-types/src/lib.rs request and response contracts
  -> layout engine and platform adapter
  -> X11 or Wayland adapter

commands.ts defines the webview calls for bootstrap data, windows, layouts, settings, arrangement, and diagnostics. app_shell.rs owns the Tauri command boundary, loads persistence, gathers screens/windows, and passes arrangement requests onward.

shared-types/src/lib.rs is the Rust source of the serializable IPC shapes, including Layout, Settings, ArrangeRequest, ArrangeResult, and adapter capability data.

layout_engine.rs turns a persisted layout plus a screen work area into zone rectangles and validates layout bounds. arrange_orchestrator.rs performs all-assignment validation before invoking adapter geometry paths, restores minimized windows, and adjusts requested geometry for frame extents. platform_adapter.rs defines the abstraction used by X11, Wayland, and tests.

The platform boundary is intentionally important: X11 is the only intended adapter path for movement, but its actual move/resize behavior is unverified because it constructs the wrong client-message type. The Wayland adapter supplies read-only window data and reports arrangement as unsupported.