Add border around ship deck

- Draw 4px border outline around deck area
- Uses dark brown color matching planks
- Transparent fill to show planks underneath
- Clearly defines deck boundaries

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/scenes/ShipDeckScene.js

@@ -57,6 +57,12 @@ export default class ShipDeckScene extends Phaser.Scene {
             this.add.rectangle(this.deckCenterX, this.deckTopY + i * this.deckPlankSpacing, this.deckWidth, 25, 0x654321)
                 .setStrokeStyle(2, 0x3d2817);
         }
+
+        // Draw border around deck
+        const deckHeight = this.deckBottomY - this.deckTopY + 25; // +25 for last plank height
+        const deckBorder = this.add.rectangle(this.deckCenterX, this.deckTopY + (deckHeight / 2), this.deckWidth, deckHeight);
+        deckBorder.setStrokeStyle(4, 0x3d2817);
+        deckBorder.setFillStyle(0x000000, 0); // Transparent fill
     }
 
     createBarrels() {