Make a little crossed swords combat indicator show up.

src/gui/fsm.cpp

@@ -282,10 +282,10 @@ namespace gui {
         $systems.runPickup();
         break;
       case COMBAT_START:
-        fmt::println("!!!!!!!!!!!!!! COMBAT START in IDLE");
+        $main_ui.show_combat();
         break;
       case COMBAT_STOP:
-        fmt::println("!!!!!!!!!!!!!! COMBAT STOP in IDLE");
+        $main_ui.close_combat();
         break;
       default:
         break; // ignore everything else

src/gui/main_ui.cpp

@@ -157,4 +157,12 @@ namespace gui {
       $window.draw(*$hand.sprite);
     }
   }
+
+  void MainUI::show_combat() {
+    $overlay_ui.show_sprite("top_right", "combat_active");
+  }
+
+  void MainUI::close_combat() {
+    $overlay_ui.close_sprite("top_right");
+  }
 }

src/gui/main_ui.hpp

@@ -51,5 +51,7 @@ namespace gui {
     void play_hands();
     bool hands_playing();
     void render_hands();
+    void show_combat();
+    void close_combat();
   };
 }