fix(search): 统一 Tab 样式并优化搜索结果布局

- 将 Tab 样式统一为与 plan 页面一致（padding: 24rpx）
- 移除 Tab 的固定高度，改为自适应
- 优化搜索结果计数位置（从滚动区域内移到外部）
- 移除空状态图片，使用纯文字提示
- 调整列表容器布局，移除多余的 padding

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

@@ -45,20 +45,20 @@
         </template>
       </nut-tabs>
 
+      <!-- Result Count -->
+      <view v-if="searchResults.length > 0" class="text-[#6B7280] text-[24rpx] mb-[24rpx]">
+        找到 {{ searchResults.length }} 个相关结果
+      </view>
+
       <!-- 可滚动列表区域 -->
       <view
-        class="flex-1 min-h-0 overflow-y-auto px-[40rpx] pb-[calc(160rpx+env(safe-area-inset-bottom))] box-border"
+        class="flex-1 min-h-0 overflow-y-auto pb-[calc(160rpx+env(safe-area-inset-bottom))] box-border"
       >
         <!-- Search Results -->
         <view
           v-if="searchResults.length > 0"
           :key="listRenderKey"
         >
-          <!-- Result Count -->
-          <view class="text-[#6B7280] text-[24rpx] mb-[24rpx]">
-            找到 {{ searchResults.length }} 个相关结果
-          </view>
-
           <!-- Results List -->
           <view class="flex flex-col gap-[24rpx] pb-[40rpx]">
             <!-- Product/Material Card -->
@@ -112,11 +112,11 @@
 
         <!-- Empty State (已搜索但无结果) -->
         <view v-else-if="hasSearched && searchResults.length === 0" class="flex flex-col items-center justify-center py-[120rpx]">
-          <image
+          <!-- <image
             class="w-[320rpx] h-[320rpx] mb-[40rpx]"
             src="https://picsum.photos/seed/empty/320/320"
             mode="aspectFit"
-          />
+          /> -->
           <view class="text-[#6B7280] text-[28rpx]">暂无搜索结果</view>
           <view class="text-[#9CA3AF] text-[24rpx] mt-[12rpx]">试试其他关键词吧</view>
         </view>
@@ -406,7 +406,7 @@ watch(searchKeyword, (newVal) => {
 .filter-tabs-wrapper {
   display: flex;
   overflow-x: auto;
-  padding: 0;
+  padding: 24rpx 24rpx;
   gap: 24rpx;
   transition: all 0.3s ease;
   background-color: #F9FAFB;
@@ -432,7 +432,6 @@ watch(searchKeyword, (newVal) => {
   white-space: nowrap;
   transition: all 0.3s ease;
   flex-shrink: 0;
-  height: 64rpx;
 }
 
 .filter-tab-active {