fix: update refs handling in RickGamePanel for improved canvas access

source/src/index.tsx

@@ -1,6 +1,7 @@
 import { h, render, Component } from 'nano-jsx'
 
 class RickGamePanel extends Component {
+  refs: { [key: string]: any } = {}
   canvas?: HTMLCanvasElement
   ctx?: CanvasRenderingContext2D
   x = 20
@@ -59,13 +60,14 @@ class RickGamePanel extends Component {
   }
 
   mounted() {
-    this.canvas = this.ref('game') as HTMLCanvasElement
+    this.canvas = this.refs['game'] as HTMLCanvasElement
     this.ctx = this.canvas?.getContext('2d') || undefined
 
     this.canvas?.addEventListener('click', this.handleJump)
     this.frame()
   }
 
+
   render() {
     return (
       <div