refactors the application structure to move away from a monolithic
`main.rs`.
- **Domain Models**: Extracted `State`, `Message`, `FileAction`, and
`ViewAction` into `state.rs` and `message.rs`. Enforced encapsulation on
`State` using private fields and public accessors.
- **Controller Layer**: Created `handler.rs` to handle business logic
and I/O operations, transforming the main `update` loop into a pure
event router.
- **Component System**: Split the UI into composable, stateless
functions in `components/` (tabs, editor, status_bar, action_bar),
removing the 100+ line view function.
- **File Logic**: Encapsulated file operations and safe path handling
within `file.rs`, removing fragile `expect` calls from the UI layer.
- **Utilities**: Centralized static configuration, keybindings, and I/O
helpers into `constants.rs`, `key_bindings.rs`, and `io.rs`.
This change decouples the view from the model and makes the core
application logic testable
Stevan Freeborn