将操作说明拆分为独立游戏规则页面并精简主界面侧栏

src/source/TetrisLogic.cpp

@@ -687,7 +687,7 @@ void ReturnToMainMenu()
     currentScreen = SCREEN_MENU;
     suspendFlag = false;
     gameOverFlag = false;
-    menuState.optionCount = 2;
+    menuState.optionCount = 3;
     upgradeUiState.pendingCount = 0;
 
     if (menuState.selectedIndex < 0 || menuState.selectedIndex >= menuState.optionCount)
@@ -696,6 +696,12 @@ void ReturnToMainMenu()
     }
 }
 
+void OpenRulesScreen()
+{
+    currentScreen = SCREEN_RULES;
+    suspendFlag = false;
+}
+
 void OpenUpgradeMenu()
 {
     if (currentMode != MODE_ROGUE || upgradeUiState.pendingCount <= 0)