Add tab navigation for building and recruitment UI

- Add selection indices and option lists to SkirmishState.
- Implement `cycle_popup_option` and expose Left/Right actions in
  keybindings.
- Introduce `cancel_focused_tasks` in BoardState for Delete handling.
- CellWidget now displays recruitment progress on Base structures.
- Update README and documentation to describe new tabs and arrow
  navigation.
- Adjust test counts and add extensive task‑cancellation tests.

tests/context_keybindings.rs

@@ -77,7 +77,7 @@ fn building_view_has_its_own_help_and_does_not_build_on_invalid_tile() -> () {
     assert!(app.states_ref().unwrap().skirmish.building_view);
     assert_eq!(
         available_skirmish_actions(&app.states_ref().unwrap().skirmish),
-        [Action::Building, Action::Esc, Action::Quit2]
+        [Action::Building, Action::Left, Action::Right, Action::Quit2]
     );
     press(&mut app, KeyCode::Left, KeyModifiers::NONE);
     press(&mut app, KeyCode::Enter, KeyModifiers::NONE);
@@ -99,7 +99,11 @@ fn building_view_has_its_own_help_and_does_not_build_on_invalid_tile() -> () {
     assert!(text.contains("Construction unavailable"));
     assert!(text.contains("Close buildings"));
     assert!(!text.contains("Marking cells"));
+    assert!(!text.contains("Esc -"));
     press(&mut app, KeyCode::Esc, KeyModifiers::NONE);
+    assert!(app.states_ref().unwrap().skirmish.building_view);
+    assert_eq!(app.view, View::Skirmish);
+    press(&mut app, KeyCode::Char('b'), KeyModifiers::NONE);
     assert!(!app.states_ref().unwrap().skirmish.building_view);
     assert_eq!(app.view, View::Skirmish);
     for row in &app.states_ref().unwrap().skirmish.board.cells {
@@ -183,7 +187,7 @@ fn construction_and_recruitment_popups_render_semantic_text_colors() -> () {
             .unwrap();
         let cells: &[Cell] = &terminal.backend().buffer().content;
         for (text, color) in [
-            (name, Color::Yellow),
+            (name, Color::LightMagenta),
             ("Cost:", Color::Yellow),
             (status, status_color),
         ] {
@@ -203,3 +207,31 @@ fn construction_and_recruitment_popups_render_semantic_text_colors() -> () {
         }
     }
 }
+
+#[test]
+fn popup_tabs_cycle_without_moving_map_or_changing_queues() -> () {
+    for key in ['b', 'r'] {
+        let mut app: App = app();
+        if key == 'r' {
+            press(&mut app, KeyCode::Left, KeyModifiers::NONE);
+        }
+        let before: war_in_tunnels::app::states::skirmish_states::BoardState =
+            app.states_ref().unwrap().skirmish.board.clone();
+        press(&mut app, KeyCode::Char(key), KeyModifiers::NONE);
+        for code in [KeyCode::Left, KeyCode::Right, KeyCode::Right, KeyCode::Left] {
+            press(&mut app, code, KeyModifiers::NONE);
+            let state: &war_in_tunnels::app::states::SkirmishState =
+                &app.states_ref().unwrap().skirmish;
+            assert_eq!(state.board, before);
+            assert_eq!(state.selected_building, 0);
+            assert_eq!(state.selected_recruit, 0);
+            assert!(available_skirmish_actions(state).contains(&Action::Left));
+            assert!(available_skirmish_actions(state).contains(&Action::Right));
+        }
+        press(&mut app, KeyCode::Esc, KeyModifiers::NONE);
+        assert_eq!(app.view, View::Skirmish);
+        press(&mut app, KeyCode::Char(key), KeyModifiers::NONE);
+        assert!(!app.states_ref().unwrap().skirmish.building_view);
+        assert!(!app.states_ref().unwrap().skirmish.recruitment_view);
+    }
+}