remove unused files

slides/components/Counter.vue

-<script setup lang="ts">
-import { ref } from 'vue'
-
-const props = defineProps({
-  count: {
-    default: 0,
-  },
-})
-
-const counter = ref(props.count)
-</script>
-
-<template>
-  <div flex="~" w="min" border="~ main rounded-md">
-    <button
-      border="r main"
-      p="2"
-      font="mono"
-      outline="!none"
-      hover:bg="gray-400 opacity-20"
-      @click="counter -= 1"
-    >
-      -
-    </button>
-    <span m="auto" p="2">{{ counter }}</span>
-    <button
-      border="l main"
-      p="2"
-      font="mono"
-      outline="!none"
-      hover:bg="gray-400 opacity-20"
-      @click="counter += 1"
-    >
-      +
-    </button>
-  </div>
-</template>