Decouple travel and cooking fuel mechanics

- Travel is now free (no fuel cost for sailing between locations)
- Fuel is only consumed for cooking whale oil (2 fuel per whale)
- Updated TransitionScene to show "The wind carries your sails..." when no fuel cost
- Removed fuel checks from MapScene travel methods
- Added fuel validation in HuntingScene - can't process whales without fuel
- This sets up the penguin burning mechanic for when cooking fuel runs low

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

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

src/scenes/TransitionScene.js

@@ -45,11 +45,19 @@ export default class TransitionScene extends Phaser.Scene {
             wordWrap: { width: 660 }
         }).setOrigin(0.5);
 
-        // Fuel cost display
-        this.add.text(400, 500, `Fuel consumed: ${this.fuelCost} units`, {
-            fontSize: '16px',
-            fill: '#ffff00'
-        }).setOrigin(0.5);
+        // Fuel cost display (only if there's a cost)
+        if (this.fuelCost > 0) {
+            this.add.text(400, 500, `Fuel consumed: ${this.fuelCost} units`, {
+                fontSize: '16px',
+                fill: '#ffff00'
+            }).setOrigin(0.5);
+        } else {
+            this.add.text(400, 500, 'The wind carries your sails...', {
+                fontSize: '16px',
+                fill: '#cccccc',
+                fontStyle: 'italic'
+            }).setOrigin(0.5);
+        }
 
         // Continue button
         const continueBtn = this.add.rectangle(400, 540, 200, 50, 0x2d5f8e);
@@ -72,8 +80,10 @@ export default class TransitionScene extends Phaser.Scene {
         });
 
         continueBtn.on('pointerdown', () => {
-            // Deduct fuel
-            this.inventory.fuel -= this.fuelCost;
+            // Deduct fuel (if any cost)
+            if (this.fuelCost > 0) {
+                this.inventory.fuel -= this.fuelCost;
+            }
 
             // Proceed to next scene
             this.scene.start(this.nextScene, { inventory: this.inventory });