feat: add k-launcher-ui-egui crate for enhanced UI

- Introduced a new crate `k-launcher-ui-egui` to provide a graphical user interface using eframe and egui.
- Updated the workspace configuration in `Cargo.toml` to include the new crate.
- Implemented the main application logic in `src/app.rs`, handling search functionality and user interactions.
- Created a library entry point in `src/lib.rs` to expose the `run` function for launching the UI.
- Modified the `k-launcher` crate to include a new binary target for the egui-based launcher.
- Added a new main file `src/main_egui.rs` to initialize and run the egui UI with the existing kernel and launcher components.

Cargo.toml

@@ -8,6 +8,7 @@ members = [
     "crates/plugins/plugin-calc",
     "crates/plugins/plugin-cmd",
     "crates/plugins/plugin-files",
+    "crates/k-launcher-ui-egui",
 ]
 resolver = "2"