fix: 修复虚拟键盘光标移位退格暴露的问题

src/components/common/FTInput/index.vue

@@ -180,12 +180,18 @@ const ignoreBlur = ref(false)
 
 const handleBackspace = () => {
   ignoreBlur.value = true
-  // const position = keyboard.value.getCaretPosition()
-  // console.log(position)
-  const value = model.value?.toString() || ''
-  model.value = value.slice(0, -1)
+  const input = model.value?.toString() || ''
+  let index: number | null
 
-  console.log(model.value)
+  // 有选中文本时删除整个选区
+  const start = keyboard.value.getCaretPosition()
+  const end = keyboard.value.getCaretPositionEnd()
+  model.value = input.slice(0, start) + input.slice(end)
+  // eslint-disable-next-line prefer-const
+  index = start
+
+  // 更新光标位置
+  keyboard.value.setCaretPosition(index)
   // 设置短时间延迟恢复 blur 监听
   setTimeout(() => {
     ignoreBlur.value = false