opt: 优化 ItemList 组件样式

web/src/components/ItemList.vue

@@ -47,7 +47,7 @@ onMounted(() => {
 const computeSize = () => {
   const w = container.value.offsetWidth - 8 // 减去滚动条的宽度
   let cols = Math.floor(w / props.width)
-  itemWidth.value = Math.floor(w / cols)
+  itemWidth.value = Math.ceil(w / cols) - 1
 }
 
 window.onresize = () => {