chore: add example menu demo

src/main.cpp

@@ -6,6 +6,14 @@
 Joystick joystick;
 Display display;
 
+Item items[MENU_ITEM_COUNT] = {
+  {"Feed", []() { Serial.println("Feeding..."); }},
+  {"Play", []() { Serial.println("Playing..."); }},
+  {"Sleep", []() { Serial.println("Sleeping..."); }},
+  {"Clean", []() { Serial.println("Cleaning..."); }}
+};
+Menu menu(items);
+
 void setup() {
   Serial.begin(9600);
   while (!Serial) {
@@ -14,7 +22,19 @@ void setup() {
 
   display.begin();
   pinMode(LED_BUILTIN, OUTPUT);
+  display.drawMenu(menu);
 }
 
 void loop() {
+  JoystickDirection direction = joystick.getDirection();
+  if (direction != JoystickDirection::CENTER) {
+    menu.updateCurrentItem(direction);
+    display.drawMenu(menu);
+  }
+
+  if (joystick.isPressed()) {
+    menu.execute();
+  }
+
+  delay(250);
 }