Add velocity HUD display (Velocity: 0) in top-left corner

src/Game.cpp

@@ -1216,8 +1216,13 @@ namespace ZL
 			}
 
 			// update velocity text
-			std::string velocityStr = "Velocity: " + std::to_string(static_cast<int>(Environment::shipState.velocity));
-			uiManager.setText("velocityText", velocityStr);
+			if (shipAlive && !gameOver) {
+				auto velocityTv = uiManager.findTextView("velocityText");
+				if (velocityTv) {
+					std::string velocityStr = "Velocity: " + std::to_string(static_cast<int>(Environment::shipState.velocity));
+					uiManager.setText("velocityText", velocityStr);
+				}
+			}
 
 			uiManager.update(static_cast<float>(delta));
 			lastTickCount = newTickCount;