fix: 修复几何坐标轴绘制范围问题

webui/src/components/Geometry.vue

@@ -95,7 +95,7 @@ const calculateRange = () => {
   const allHeights = [...hArmNums, ...actualHeights, 0]
   const allX = [...gcXNums, -gcXNums[0] * 0.5, gcXNums[0] * 1.5] // 扩展水平范围
   
-  const yMin = 0
+  const yMin = -10
   const yMax = Math.max(...allHeights) * 1.15
   const xMin = Math.min(...allX) * 1.2
   const xMax = Math.max(...allX) * 1.2
@@ -157,8 +157,8 @@ const draw = () => {
 
   // X 轴（地面）
   ctx.beginPath()
-  ctx.moveTo(margin.left, toCanvasY(0, range))
-  ctx.lineTo(margin.left + plotWidth, toCanvasY(0, range))
+  ctx.moveTo(margin.left, toCanvasY(range.yMin, range))
+  ctx.lineTo(margin.left + plotWidth, toCanvasY(range.yMin, range))
   ctx.stroke()
 
   // 绘制刻度标签