Add basic common_ui background gfx functions (#415)

* Add basic common_ui background gfx functions

* clang format

* document common_ui.h

* Remove unused tonc header

* Fix header guard name convention

* more header cleanup

* claaaaanggggg format

include/game.h

@@ -1,6 +1,7 @@
 #ifndef GAME_H
 #define GAME_H
 
+#include "game/common_ui.h"
 #include "game_variables.h"
 
 #include <tonc.h>
@@ -38,17 +39,6 @@ typedef struct CardObject CardObject;
 typedef struct Card Card;
 typedef struct JokerObject JokerObject;
 
-enum BackgroundId
-{
-    BG_NONE,
-    BG_CARD_SELECTING,
-    BG_CARD_PLAYING,
-    BG_ROUND_END,
-    BG_SHOP,
-    BG_BLIND_SELECT,
-    BG_MAIN_MENU
-};
-
 // Enum value names in ../include/def_state_info_table.h
 enum GameState
 {
@@ -182,4 +172,9 @@ void set_game_speed(int new_game_speed);
 bool is_shortcut_joker_active(void);
 int get_straight_and_flush_size(void);
 
+// Temporary change for Refactor. Currently this compatibility binder is to allow
+// simultaneous integration of the new system in `common_ui` with the the existing
+// old system incrementally and without losing functionality.
+void change_background_legacy(enum BackgroundId id);
+
 #endif // GAME_H