Add audio assets and integrate music/SFX handling

- Added new sound effect and music MP3 files to the project.
- Updated **BootScene** to preload all music tracks and sound effects.
- Implemented music playback:
  * MenuScene now plays looping title music and stops it on shutdown.
  * GameScene now stops any playing music on shutdown and starts level‑specific background music with fallback to the last track.
- Added SFX triggers for player shooting, alien shooting, missile launch, impacts, alien death, and player death.
- Cleaned up formatting and minor code style issues in GameScene (group/array declarations, tweens, UI text creation, level setup loops, etc.).
- Ensured proper cleanup of music objects when scenes change.

js/scenes/BootScene.js

@@ -7,6 +7,24 @@ export default class BootScene extends Phaser.Scene {
         super({ key: 'BootScene' });
     }
 
+    preload() {
+        this.load.audio('title',   'js/audio/music/title.mp3');
+        this.load.audio('track01', 'js/audio/music/track01.mp3');
+        this.load.audio('track02', 'js/audio/music/track02.mp3');
+        this.load.audio('track03', 'js/audio/music/track03.mp3');
+        this.load.audio('track04', 'js/audio/music/track04.mp3');
+        this.load.audio('track05', 'js/audio/music/track05.mp3');
+        this.load.audio('track06', 'js/audio/music/track06.mp3');
+        this.load.audio('track07', 'js/audio/music/track07.mp3');
+
+        this.load.audio('sfx_player_shoot', 'js/audio/fx/player_shoot.mp3');
+        this.load.audio('sfx_player_death', 'js/audio/fx/player_death.mp3');
+        this.load.audio('sfx_alien_shoot',  'js/audio/fx/alien_shoot.mp3');
+        this.load.audio('sfx_missle',       'js/audio/fx/missle.mp3');
+        this.load.audio('sfx_impact',       'js/audio/fx/impact.mp3');
+        this.load.audio('sfx_alien_death',  'js/audio/fx/alien_death.mp3');
+    }
+
     create() {
         this._createTextures();
         this.scene.start('MenuScene');

js/scenes/GameScene.js

@@ -49,6 +49,9 @@ export default class GameScene extends Phaser.Scene {
             this.cameras.main.setPostPipeline('CRTPipeline');
         }
 
+        // Stop level music when this scene shuts down (e.g. returning to menu)
+        this.events.once('shutdown', () => { if (this.music) this.music.stop(); });
+
         // Custom reticle cursor – hide the OS cursor and draw our own
         this.game.canvas.style.cursor = 'none';
         this.reticleOuter = this.add.image(800, 450, 'reticle_outer').setDepth(20);
@@ -115,6 +118,16 @@ export default class GameScene extends Phaser.Scene {
 
     // ─── Level Management ────────────────────────────────────────────────────
 
+    _playLevelMusic() {
+        if (this.music) { this.music.stop(); this.music.destroy(); this.music = null; }
+        const trackNum = String(this.level).padStart(2, '0');
+        const key = `track${trackNum}`;
+        // Fall back to the highest available track if this level doesn't have one yet
+        const resolvedKey = this.cache.audio.exists(key) ? key : 'track07';
+        this.music = this.sound.add(resolvedKey, { loop: true, volume: 0.7 });
+        this.music.play();
+    }
+
     startLevel() {
         this.levelComplete = false;
 
@@ -144,6 +157,7 @@ export default class GameScene extends Phaser.Scene {
 
         this.updateUI();
         this.showMessage(`LEVEL ${this.level}`, 2000);
+        this._playLevelMusic();
     }
 
     // Random position along any screen edge, away from center
@@ -186,18 +200,21 @@ export default class GameScene extends Phaser.Scene {
     }
 
     spawnPlayerBullet(x, y, angle) {
+        this.sound.play('sfx_player_shoot', { volume: 0.2 });
         this.playerBullets.push(
             new Bullet(this, x, y, angle, 'player', this.playerBulletsGroup)
         );
     }
 
     spawnAlienBullet(x, y, angle, ownerShip = null) {
+        this.sound.play('sfx_alien_shoot', { volume: 0.45 });
         this.alienBullets.push(
             new Bullet(this, x, y, angle, 'alien', this.alienBulletsGroup, ownerShip)
         );
     }
 
     spawnHomingMissile(x, y, ownerShip) {
+        this.sound.play('sfx_missle', { volume: 0.5 });
         const player = this.player;
         const angle = Phaser.Math.RadToDeg(
             Math.atan2(player.sprite.y - y, player.sprite.x - x)
@@ -233,6 +250,7 @@ export default class GameScene extends Phaser.Scene {
 
         this.addScore(200);
         this.spawnImpactSparks(bulletSprite.x, bulletSprite.y);
+        this.sound.play('sfx_alien_death', { volume: 0.65 });
         alien.explode();
         this.aliens = this.aliens.filter(a => a !== alien);
 
@@ -276,6 +294,7 @@ export default class GameScene extends Phaser.Scene {
     handlePlayerHit() {
         if (!this.player.hit()) return; // invincible – ignore
 
+        this.sound.play('sfx_player_death', { volume: 0.7 });
         this.player.die(); // hide ship and go invincible immediately
         this.lives--;
         this.updateUI();
@@ -319,6 +338,7 @@ export default class GameScene extends Phaser.Scene {
     }
 
     spawnImpactSparks(x, y) {
+        this.sound.play('sfx_impact', { volume: 1.0 });
         const count = Phaser.Math.Between(3, 5);
         for (let i = 0; i < count; i++) {
             const gfx = this.add.graphics();

js/scenes/MenuScene.js

@@ -46,6 +46,11 @@ export default class MenuScene extends Phaser.Scene {
         if (this.renderer.type === Phaser.WEBGL) {
             this.cameras.main.setPostPipeline('CRTPipeline');
         }
+
+        // Title music — looping; stop when this scene shuts down
+        this.music = this.sound.add('title', { loop: true, volume: 0.7 });
+        this.music.play();
+        this.events.once('shutdown', () => { if (this.music) this.music.stop(); });
     }
 
     update() {