feat: initialize project with event order form

This commit establishes the initial structure of the Nuxt application, centered around a new event order form.

Key changes include:
- Setting up the main app layout with a header, footer, and color mode support using @nuxt/ui.
- Creating a multi-part event order form on the index page.
- Introducing a `useEventOrder` composable to manage form state and validation with Zod.
- Adding modular form components under `app/components/eventOrder`.
- Including project configuration files for pnpm, VSCode, and global CSS.

app/components/eventOrder/ProductBackgroundDesign.vue

@@ -0,0 +1,78 @@
+<template>
+  <UCard>
+    <template #header>
+      <h2 class="text-xl font-bold">{{ secIdx }}. 背景设计</h2>
+      <p class="text-muted text-sm">自研动态背景效果，可以自定义形象动态图。</p>
+    </template>
+
+    <div class="grid grid-cols-1 sm:grid-cols-2 gap-4">
+      <UCheckbox
+        v-model="orderState.backgroundDesign"
+        label="订阅服务"
+        description="默认屏幕尺寸为 1920 &times; 1080。须和屏幕供应单位获取详细尺寸，确保展示无误。"
+      />
+
+      <div
+        v-if="orderState.backgroundDesign"
+        :class="['grid', 'grid-cols-1', 'gap-4']"
+      >
+        <UFormField name="backgroundType">
+          <URadioGroup
+            v-model="orderState.backgroundType"
+            color="primary"
+            variant="table"
+            default-value="static"
+            :items="backgroundTypeSelection"
+            orientation="horizontal"
+          />
+        </UFormField>
+        <div class="flex gap-4">
+          <UFormField
+            label="屏宽"
+            name="backgroundWidthOverride"
+            class="flex-1"
+          >
+            <UInput
+              type="number"
+              v-model="orderState.backgroundWidthOverride"
+              placeholder="1920"
+              class="w-full"
+            />
+          </UFormField>
+          <span class="text-2xl">&times;</span>
+          <UFormField
+            label="屏高"
+            name="backgroundHeightOverride"
+            class="flex-1"
+          >
+            <UInput
+              type="number"
+              v-model="orderState.backgroundHeightOverride"
+              placeholder="1080"
+              class="w-full"
+            />
+          </UFormField>
+        </div>
+      </div>
+    </div>
+  </UCard>
+</template>
+
+<script lang="ts" setup>
+import type { RadioGroupItem } from "@nuxt/ui";
+
+const { sectionIndex, orderState } = useEventOrder();
+
+const secIdx = ref(++sectionIndex.value);
+
+const backgroundTypeSelection = ref<RadioGroupItem[]>([
+  { label: "静态背景图", value: "static" },
+  {
+    label: "动态背景图",
+    value: "dynamic",
+    description: "由于技术原因，不能保证每次都能对成果进行微调。",
+  },
+]);
+</script>
+
+<style></style>