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/HuntingScene.js

@@ -1,4 +1,5 @@
 import Phaser from 'phaser';
+import { fontSize } from '../utils/responsive.js';
 
 export default class HuntingScene extends Phaser.Scene {
     constructor() {
@@ -196,7 +197,7 @@ export default class HuntingScene extends Phaser.Scene {
 
         // Stats (fixed to screen)
         this.statsText = this.add.text(20, 15, '', {
-            fontSize: '16px',
+            fontSize: fontSize(16),
             fill: '#fff'
         });
         this.statsText.setScrollFactor(0);
@@ -204,7 +205,7 @@ export default class HuntingScene extends Phaser.Scene {
         // Control mode indicator (fixed to screen, desktop only)
         if (!this.isMobile) {
             this.controlModeText = this.add.text(400, 15, 'Controls: MOUSE (TAB to switch)', {
-                fontSize: '16px',
+                fontSize: fontSize(16),
                 fill: '#ffff00'
             }).setOrigin(0.5, 0);
             this.controlModeText.setScrollFactor(0);
@@ -217,7 +218,7 @@ export default class HuntingScene extends Phaser.Scene {
         returnBtn.setScrollFactor(0);
 
         const returnText = this.add.text(750, 30, 'RETURN', {
-            fontSize: '14px',
+            fontSize: fontSize(14),
             fill: '#fff'
         }).setOrigin(0.5);
         returnText.setScrollFactor(0);
@@ -239,7 +240,7 @@ export default class HuntingScene extends Phaser.Scene {
 
     createInstructions() {
         this.messageText = this.add.text(400, 570, '', {
-            fontSize: '16px',
+            fontSize: fontSize(16),
             fill: '#fff',
             backgroundColor: '#000000',
             padding: { x: 10, y: 5 }