feat(pricing): introduce real-time budget estimator

This commit introduces a real-time budget estimator for event services. A new summary sidebar now displays a live,
itemized breakdown of costs as the user selects options in the order form.

Key changes include:
- A new `OrderSummary` component to display the price breakdown and total.
- Comprehensive pricing logic implemented in the `useEventOrder` composable.
- A responsive two-column layout on the main page to accommodate the summary.
- UI/UX improvements across the form, including clearer labels and subtle transition animations for conditional fields.

app/components/eventOrder/ProductSponsor.vue

@@ -1,17 +1,15 @@
 <template>
   <UCard>
     <template #header>
-      <h2 class="text-xl font-bold">{{ secIdx }}. 赞助商名册</h2>
+      <h2 class="text-xl font-bold">{{ secIdx }}. 赞助商位</h2>
       <p class="text-muted text-sm">
+        可制作<strong>赞助页</strong>，含标志排版与统一风格。
         附送一个<strong>基础款</strong>手机端电子征信录，可定制（另计）
       </p>
     </template>
 
     <div class="grid grid-cols-1 sm:grid-cols-3 gap-4 items-center">
-      <UCheckbox
-        v-model="orderState.sponsorListDesign"
-        label="订阅服务"
-      />
+      <UCheckbox v-model="orderState.sponsorListDesign" label="需要" />
     </div>
   </UCard>
 </template>