feat(item): add delete functionality

This commit introduces the ability to delete items. A new `ItemDeleteModal` component provides a confirmation step
before removal.

- Adds a 'Delete' option to the action menu in the items table.
- Refactors the `useItems` composable to ensure reactivity with `useLocalStorage` by creating new array references on
add/remove operations.
- Renames `AddModal` to `EditModal` to better align with its future role in both adding and editing items.

app/components/item/DeleteModal.vue

@@ -0,0 +1,53 @@
+<template>
+  <UModal
+    v-model:open="open"
+    :title="`删除 ${item?.name}？`"
+    :description="`确定吗？此操作不可被还原。`"
+  >
+    <slot />
+
+    <template #body>
+      <div class="flex justify-end gap-2">
+        <UButton
+          label="Cancel"
+          color="neutral"
+          variant="subtle"
+          @click="open = false"
+        />
+        <UButton
+          label="Delete"
+          color="error"
+          variant="solid"
+          loading-auto
+          @click="onSubmit"
+        />
+      </div>
+    </template>
+  </UModal>
+</template>
+
+<script lang="ts" setup>
+const props = withDefaults(
+  defineProps<{
+    item?: Item | null;
+  }>(),
+  {
+    item: null,
+  }
+);
+
+const { removeItem } = useItemsStore();
+
+const open = defineModel<boolean>("open", { default: false });
+
+async function onSubmit() {
+  // await new Promise((resolve) => setTimeout(resolve, 1000));
+  if (!props.item || props.item.id == null) {
+    return;
+  }
+  removeItem(props.item.id);
+  open.value = false;
+}
+</script>
+
+<style></style>