refactor: build decoupled input processing & add event queue system

src/game/events.rs

@@ -0,0 +1,12 @@
+use crate::input::commands::GameCommand;
+
+#[derive(Debug, Clone, Copy)]
+pub enum GameEvent {
+    InputCommand(GameCommand),
+}
+
+impl From<GameCommand> for GameEvent {
+    fn from(command: GameCommand) -> Self {
+        GameEvent::InputCommand(command)
+    }
+}