This introduces a new Tauri command to clone a remote repository into a
validated destination folder, then return the full repository bundle for
immediate rendering. The Svelte app gains a clone dialog and a new action
in repository management, wiring the cloned bundle into existing refresh
helpers. Dialog backdrops were also adjusted to rely on explicit close
controls.
- Add clone_repository command and core cloning logic in Rust
- Create CloneRepositoryDialog and integrate it into App.svelte
- Improve clone-related styling and tighten dialog backdrop behavior