feat: Add audio assets and pre-caching

This commit introduces audio functionality to the game by integrating the `flame_audio` package.

- **Initialization**: The `FlameAudio` engine is initialized at the start of the application.
- **Asset Pre-caching**: All necessary audio files, including background music (`background.mp3`) and sound effects (`collide-bat.wav`, `collide-brick.wav`, `win.wav`, `game-over.wav`), are pre-loaded into the audio cache on app startup to ensure they are ready for playback without delay.

Author: Ayush2006128

lib/main.dart

@@ -1,10 +1,19 @@
 import 'package:flutter/material.dart';
 import 'package:hive_flutter/hive_flutter.dart';
+import 'package:flame_audio/flame_audio.dart';
 
 import 'src/widgets/game_app.dart';
 
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
+  FlameAudio.bgm.initialize();
+  FlameAudio.audioCache.loadAll([
+    "background.mp3",
+    "collide-bat.wav",
+    "collide-brick.wav",
+    "win.wav",
+    "game-over.wav",
+  ]);
 
   await Hive.initFlutter();
   await Hive.openBox('bricked');

lib/src/brick_breaker.dart

@@ -64,8 +64,6 @@ class BrickBreaker extends FlameGame
     highScore.value = Hive.box('bricked').get('highScore', defaultValue: 0);
 
     playState = PlayState.welcome;
-    FlameAudio.bgm.initialize();
-
   }
 
   void startGame() {
@@ -78,7 +76,7 @@ class BrickBreaker extends FlameGame
     playState = PlayState.playing;
     score.value = 0;
     newHighScoreAchieved = false;
-    FlameAudio.bgm.play("background.mp3");
+    FlameAudio.bgm.play("background.mp3", volume: 0.7);
     world.add(
       Ball(
         difficultyModifier: difficultyModifier,

lib/src/components/ball.dart

@@ -56,6 +56,7 @@ class Ball extends CircleComponent
             },
           ),
         );
+        FlameAudio.bgm.stop();
         FlameAudio.play("game-over.wav");
       }
     } else if (other is Bat) {