feat(dominion): display opponent hand cards near portraits

- Add face-down mini card sprites for opponents below their portraits
- Implement layout logic to center and space cards based on hand size
- Update card asset textures

public/src/games/dominion/DominionGame.js

@@ -355,6 +355,22 @@ export default class DominionGame extends Phaser.Scene {
         color: active ? COLORS.goldHex : COLORS.mutedHex, align: 'center',
         backgroundColor: 'rgba(0,0,0,0.55)', padding: { x: 8, y: 4 },
       }).setOrigin(0.5).setDepth(D.hud));
+
+      // Mini face-down cards representing the opponent's hand
+      const OPP_W = 36, OPP_H = 52;
+      const handSize = p.hand.length;
+      if (handSize > 0) {
+        const gap = Math.min(4, (200 - handSize * OPP_W) / Math.max(1, handSize - 1));
+        const step = OPP_W + Math.max(-OPP_W * 0.6, gap);
+        const totalW = (handSize - 1) * step + OPP_W;
+        const startX = s.x - totalW / 2 + OPP_W / 2;
+        const cardY = s.y + s.r + 75;
+        for (let j = 0; j < handSize; j++) {
+          const mini = this.buildCardFace(OPP_W, OPP_H, null, { faceDown: true });
+          mini.setPosition(startX + j * step, cardY).setDepth(D.hud + j);
+          this.dynamicLayer.add(mini);
+        }
+      }
     });
   }