fix: square plot canvas 600x600

app/src/main/assets/console.js

@@ -524,10 +524,10 @@ class SymjaConsole {
         const canvas = document.createElement('canvas');
         canvas.className = 'plot-canvas';
         const dpr = window.devicePixelRatio || 1;
-        canvas.width = 720 * dpr;
-        canvas.height = 500 * dpr;
-        canvas.style.width = '720px';
-        canvas.style.height = '500px';
+        canvas.width = 600 * dpr;
+        canvas.height = 600 * dpr;
+        canvas.style.width = '600px';
+        canvas.style.height = '600px';
         container.appendChild(canvas);
 
         // 图例（多曲线时自动显示）