feat(dominion): add sparkle particles and coin sound to supply piles

- Add a particle emitter effect to supply pile cards using a generated sparkle texture.
- Include a `coins.mp3` sound effect for purchase interactions.
- Implement `_clearSupplyFx` to manage emitter lifecycle during render cycles.

public/src/games/dominion/DominionGame.js

@@ -100,10 +100,18 @@ export default class DominionGame extends Phaser.Scene {
     this._suppressTurnUi = false;
     this._handFxGraphics = [];
     this._handFxTweens   = [];
+    this._supplyFxEmitters = [];
   }
 
   create() {
     new MusicPlayer(this, this.cache.json.get('music').tracks);
+    if (!this.textures.exists('dominion-sparkle')) {
+      const g = this.add.graphics();
+      g.fillStyle(0xffffff, 1);
+      g.fillCircle(3, 3, 3);
+      g.generateTexture('dominion-sparkle', 6, 6);
+      g.destroy();
+    }
     this.buildBackground();
     this.buildPortraits();
     this.buildTurnArrow();
@@ -421,6 +429,7 @@ export default class DominionGame extends Phaser.Scene {
 
   render() {
     this._clearHandFx();
+    this._clearSupplyFx();
     if (this.hoverTimer) { this.hoverTimer.remove(); this.hoverTimer = null; }
     this.hideHover();
     this.dynamicLayer?.destroy(true);
@@ -500,6 +509,7 @@ export default class DominionGame extends Phaser.Scene {
         hit.setInteractive({ useHandCursor: true });
         hit.on('pointerup', () => this.humanBuy(id));
         this.markBuyable(face);
+        this._buildSupplyFxItem(x, y);
       }
     }
   }
@@ -510,6 +520,27 @@ export default class DominionGame extends Phaser.Scene {
     face.addAt(glow, 0);
   }
 
+  _clearSupplyFx() {
+    this._supplyFxEmitters.forEach(e => e.destroy());
+    this._supplyFxEmitters = [];
+  }
+
+  _buildSupplyFxItem(x, y) {
+    const emitter = this.add.particles(x, y, 'dominion-sparkle', {
+      x:         { min: -SUPPLY_W / 2 + 4, max: SUPPLY_W / 2 - 4 },
+      y:         -SUPPLY_H / 2,
+      speedX:    { min: -18, max: 18 },
+      speedY:    { min: -70, max: -30 },
+      alpha:     { start: 0.9, end: 0 },
+      scale:     { start: 0.8, end: 0.15 },
+      lifespan:  900,
+      frequency: 100,
+      tint:      [0xffffff, 0xffeebb, 0xd4a017, 0xc8a84b],
+      depth:     D.supply + 8,
+    });
+    this._supplyFxEmitters.push(emitter);
+  }
+
   renderInPlay() {
     const gs = this.gs;
     const p = gs.players[gs.turn];