- Create `GameStates` from a `&Cli` and initialize the skirmish board in
`App::new`.
- Move map dimensions to `SkirmishState` and add a `board_cells` vector
populated by `CellWidget`s.
- Refactor `SettingsState` to store only user‑specific settings (fields
are cloned).
- Update `BoardWidget` to hold a reference to the cell vector and use
the new dimensions.
- Adjust CLI defaults: map width to 50 and map height to 25.
Removed the settings UI and its keybinding logic, added a skirmish view
and corresponding keybindings, simplified the SettingsState to hold
skirmish configuration, updated module exports, and changed the CLI
default map height from 25 to 21. Also fixed the main menu selection
limit.