feat: 清理示例数据并统一空态体验

frontend/src/views/fees/ContractFeeDetail.vue

@@ -84,8 +84,10 @@
           <el-table-column :label="TEXT.common.fields.remark" min-width="200" show-overflow-tooltip>
             <template #default="scope">{{ scope.row.remark || TEXT.common.fallback }}</template>
           </el-table-column>
+          <template #empty>
+            <div class="table-empty">{{ TEXT.modules.feeContracts.paymentEmpty }}</div>
+          </template>
         </el-table>
-        <StateEmpty v-if="detail.payments.length === 0" :description="TEXT.modules.feeContracts.paymentEmpty" />
       </el-card>
 
       <el-card class="section-card unified-shell" shadow="never">
@@ -116,7 +118,6 @@ import { fetchSites } from "../../api/sites";
 import { useStudyStore } from "../../store/study";
 import { usePermission } from "../../utils/permission";
 import { displayDate } from "../../utils/display";
-import StateEmpty from "../../components/StateEmpty.vue";
 import StateError from "../../components/StateError.vue";
 import StateLoading from "../../components/StateLoading.vue";
 import FeeAttachmentPanel from "../../components/fees/FeeAttachmentPanel.vue";
@@ -307,4 +308,14 @@ onMounted(async () => {
   color: var(--ctms-text-placeholder);
   font-size: 13px;
 }
+.table-empty {
+  min-height: 220px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  color: #8a97ab;
+  font-size: 14px;
+  font-weight: 500;
+  letter-spacing: 0.02em;
+}
 </style>