feat: add responsive font sizing for mobile

- Add src/utils/responsive.js with fontSize() helper
- Mobile fonts scale 1.4x for better readability
- Update all scenes to use responsive font sizes
- Update deploy-k8s.sh with full deployment steps

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

src/scenes/IntroScene.js

@@ -1,3 +1,5 @@
+import { fontSize } from '../utils/responsive.js';
+
 export default class IntroScene extends Phaser.Scene {
     constructor() {
         super({ key: 'IntroScene' });
@@ -19,7 +21,7 @@ export default class IntroScene extends Phaser.Scene {
 
         // Game title
         const title = this.add.text(400, 150, 'WHALE HUNTING', {
-            fontSize: '56px',
+            fontSize: fontSize(56),
             fill: '#ffffff',
             fontStyle: 'bold'
         }).setOrigin(0.5);
@@ -27,7 +29,7 @@ export default class IntroScene extends Phaser.Scene {
 
         // Subtitle
         this.add.text(400, 210, 'A Whaling Adventure on the High Seas', {
-            fontSize: '22px',
+            fontSize: fontSize(22),
             fill: '#cccccc',
             fontStyle: 'italic'
         }).setOrigin(0.5);
@@ -43,7 +45,7 @@ export default class IntroScene extends Phaser.Scene {
         buttonBg.setInteractive({ useHandCursor: true });
 
         const buttonText = this.add.text(400, 400, 'SET SAIL', {
-            fontSize: '28px',
+            fontSize: fontSize(28),
             fill: '#ffffff',
             fontStyle: 'bold'
         }).setOrigin(0.5);
@@ -73,7 +75,7 @@ export default class IntroScene extends Phaser.Scene {
 
         // Instructions text
         this.add.text(400, 530, 'Click to cast off and seek yer fortune!', {
-            fontSize: '16px',
+            fontSize: fontSize(16),
             fill: '#ffff99'
         }).setOrigin(0.5);
     }