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/ProductBidding.vue

@@ -1,40 +1,49 @@
 <template>
   <UCard>
     <template #header>
-      <h2 class="text-xl font-bold">{{ secIdx }}. 宴会竞标大屏</h2>
+      <h2 class="text-xl font-bold">{{ secIdx }}. 竞标大屏系统</h2>
       <p class="text-muted text-sm">
         自研竞标展示系统，全马首创，适用于宴会、活动、庆典等场合，具备实时竞标显示功能。
       </p>
     </template>
 
-    <div class="grid grid-cols-1 sm:grid-cols-3 gap-4 items-center">
+    <div class="grid grid-cols-1 sm:grid-cols-3 gap-4">
       <UCheckbox
         v-model="orderState.biddingSystem"
-        label="订阅服务"
+        label="需要"
         description="包含图片处理 & 宴会当日技术支持（场控 / 协调）"
       />
 
-      <UCheckbox
-        v-model="orderState.biddingSystemProvideImage"
-        label="提供照片？"
-        description="活动方将发送标品图片给予本工作室"
-        :class="[orderState.biddingSystem ? '' : 'opacity-0']"
-        :disabled="!orderState.biddingSystem"
-      />
-
-      <UFormField
-        name="estimatedBidItemCount"
-        label="标品数量预估"
-        :class="[orderState.biddingSystem ? '' : 'opacity-0']"
-      >
-        <USelect
-          v-model="orderState.estimatedBidItemCount"
-          :items="itemCountRanges"
-          placeholder="请选择预估数量区间"
-          :class="['w-full']"
-          :disabled="!orderState.biddingSystem"
+      <Transition name="fade">
+        <USwitch
+          v-if="orderState.biddingSystem"
+          v-model="orderState.biddingSystemProvideImage"
+          :label="
+            orderState.biddingSystemProvideImage ? '素材自备' : '请求拍摄'
+          "
+          :description="
+            orderState.biddingSystemProvideImage
+              ? '您提供图片（我们进行后处理）'
+              : '我们需要到您单位去拍摄标品'
+          "
         />
-      </UFormField>
+      </Transition>
+
+      <Transition name="fade">
+        <UFormField
+          v-if="orderState.biddingSystem"
+          name="estimatedBidItemCount"
+          label="估算件数"
+          description="不影响计价"
+        >
+          <USelect
+            v-model="orderState.estimatedBidItemCount"
+            :items="itemCountRanges"
+            placeholder="请选择件数区间"
+            :class="['w-full']"
+          />
+        </UFormField>
+      </Transition>
     </div>
   </UCard>
 </template>