优化测量标签显示，移除前缀并调整位置

src/modules/measure/MeasureRenderer.ts

@@ -89,7 +89,7 @@ export default class MeasureRenderer extends BaseRenderer {
     const p1 = endPoint.position
 
     const dist = p0.distanceTo(p1)
-    const label = `长度 ${numberToString(dist)} m`
+    const label = `${numberToString(dist)} m`
 
     const position = new THREE.Vector3().addVectors(p0, p1).multiplyScalar(0.5)
     let labelObj: Text | CSS2DObject | undefined = objects[0].userData.labelObj
@@ -99,7 +99,7 @@ export default class MeasureRenderer extends BaseRenderer {
       objects[0].userData.labelObj = labelObj
     }
 
-    labelObj.position.set(position.x, position.y + 0.3, position.z)
+    labelObj.position.set(position.x, position.y, position.z - 0.2)
 
     if (this.useHtmlLabel) {
       labelObj.element.innerHTML = label