feat(puzzle): add stats completion sound loop and refine glow/timing logic

- Load new `sfx_stats.mp3` audio for puzzle completion stats display
- Increase glow delay from 500ms to 700ms for smoother visual transition
- Fix indentation in edge detection filter and normalize spacing in CSS/style assignments
- Stop and destroy stats sound on overlay cleanup or completion typing finish
- Start looping stats sound when typing puzzle completion stats, ensuring clean lifecycle management

js/scenes/PuzzleScene.js

@@ -108,6 +108,9 @@ class PuzzleScene extends Phaser.Scene {
     if (!this.cache.audio.exists('sfx_grab')) {
       this.load.audio('sfx_grab', 'assets/audio/fx/grab.mp3');
     }
+    if (!this.cache.audio.exists('sfx_stats')) {
+      this.load.audio('sfx_stats', 'assets/audio/fx/stats.mp3');
+    }
 
     // Music track list
     if (!this.cache.json.exists('music_tracks')) {
@@ -365,7 +368,7 @@ class PuzzleScene extends Phaser.Scene {
 
     this._edgeIds = this._pieces
       .filter(p => p.edges.top === 'flat' || p.edges.bottom === 'flat' ||
-                   p.edges.left === 'flat' || p.edges.right === 'flat')
+        p.edges.left === 'flat' || p.edges.right === 'flat')
       .map(p => p.id);
 
     const midCol = Math.ceil(this._cols / 2);
@@ -1228,7 +1231,7 @@ class PuzzleScene extends Phaser.Scene {
     if (!this._glowingPieceIds) this._glowingPieceIds = new Set();
     if (!this._glowTimers) this._glowTimers = new Map();
 
-    const GLOW_DELAY = 500; // ms a neighbor must stay in range before glow appears
+    const GLOW_DELAY = 700; // ms a neighbor must stay in range before glow appears
     const now = Date.now();
 
     // Track which neighbors are in proximity this frame
@@ -1264,8 +1267,8 @@ class PuzzleScene extends Phaser.Scene {
       [
         [20, 0.06],
         [14, 0.12],
-        [8,  0.30],
+        [8, 0.30],
-        [4,  0.70],
+        [4, 0.70],
       ].forEach(([baseLW, baseAlpha]) => {
         const lw = Math.max(1, baseLW * intensity);
         const alpha = baseAlpha * intensity;
@@ -2176,9 +2179,9 @@ class PuzzleScene extends Phaser.Scene {
     if (!this._uiLayer) return;
     const rect = this.sys.game.canvas.getBoundingClientRect();
     Object.assign(this._uiLayer.style, {
-      left:            rect.left + 'px',
+      left: rect.left + 'px',
-      top:             rect.top + 'px',
+      top: rect.top + 'px',
-      transform:       `scale(${rect.width / 1920}, ${rect.height / 1080})`,
+      transform: `scale(${rect.width / 1920}, ${rect.height / 1080})`,
     });
   }
 
@@ -2188,13 +2191,13 @@ class PuzzleScene extends Phaser.Scene {
     // except on the interactive children.
     this._uiLayer = document.createElement('div');
     Object.assign(this._uiLayer.style, {
-      position:        'fixed',
+      position: 'fixed',
-      width:           '1920px',
+      width: '1920px',
-      height:          '1080px',
+      height: '1080px',
       transformOrigin: 'top left',
-      pointerEvents:   'none',
+      pointerEvents: 'none',
-      zIndex:          '10',
+      zIndex: '10',
-      fontFamily:      'Arial, sans-serif',
+      fontFamily: 'Arial, sans-serif',
     });
     document.body.appendChild(this._uiLayer);
     this._syncOverlayToCanvas();
@@ -2811,11 +2814,13 @@ class PuzzleScene extends Phaser.Scene {
     const typeNext = () => {
       if (this._completionOverlay === null) {
         clearInterval(cursorBlink);
+        if (this._statsSound) { this._statsSound.stop(); this._statsSound.destroy(); this._statsSound = null; }
         return;
       }
 
       if (lineIdx >= lines.length) {
-        // Done — keep cursor blinking at end
+        // Done — stop stats sound, keep cursor blinking at end
+        if (this._statsSound) { this._statsSound.stop(); this._statsSound.destroy(); this._statsSound = null; }
         return;
       }
 
@@ -2855,7 +2860,9 @@ class PuzzleScene extends Phaser.Scene {
       }
     };
 
-    // Start typing after a short delay
+    // Start stats sound loop and typing after a short delay
+    this._statsSound = this.sound.add('sfx_stats', { loop: true, volume: 0.5 });
+    this._statsSound.play();
     setTimeout(typeNext, 500);
   }