feat(core): Add error types, config, and data model for items and events.

crates/pikl-core/src/lib.rs

@@ -0,0 +1,22 @@
+//! Core engine for pikl-menu. Handles filtering, navigation,
+//! hooks, and the menu event loop. No rendering or terminal
+//! deps. Frontends are separate crates that talk to this
+//! through channels.
+
+mod model;
+mod query;
+mod runtime;
+pub mod script;
+
+pub mod error;
+
+// Re-export submodules at crate root so the public API stays flat.
+pub use model::event;
+pub use model::item;
+pub use model::traits;
+pub use query::filter;
+pub use query::navigation;
+pub use runtime::hook;
+pub use runtime::input;
+pub use runtime::json_menu;
+pub use runtime::menu;