为部门管理添加搜索功能

1. 添加部门搜索框，支持搜索部门名称、编码和负责人
2. 部门负责人下拉选择已有搜索功能（show-search和filterUserOption）
3. 实时显示搜索结果数量

frontend/src/views/Settings.vue

@@ -396,9 +396,28 @@
                 style="margin-bottom: 16px;"
               />
 
+              <!-- 部门搜索框 -->
+              <div style="margin-bottom: 16px;">
+                <a-input-search
+                  v-model:value="departmentSearchText"
+                  placeholder="搜索部门名称、编码或负责人"
+                  allow-clear
+                  @search="onDepartmentSearch"
+                  @change="onDepartmentSearch"
+                  style="max-width: 400px;"
+                >
+                  <template #prefix>
+                    <Icon name="search" size="sm" />
+                  </template>
+                </a-input-search>
+                <span v-if="departmentSearchText" style="margin-left: 12px; color: #888; font-size: 13px;">
+                  找到 {{ filteredDepartments.length }} 个部门
+                </span>
+              </div>
+
               <a-table
                 :columns="departmentColumns"
-                :data-source="departments"
+                :data-source="filteredDepartments"
                 :loading="loading.departments"
                 row-key="id"
                 :pagination="{ pageSize: 10 }"
@@ -1452,6 +1471,7 @@ const brands = ref<Brand[]>([])
 const platforms = ref<Platform[]>([])
 const categories = ref<Category[]>([])
 const departments = ref<DepartmentOverview[]>([])
+const departmentSearchText = ref<string>('')
 const currentScorePool = ref<TeamScorePool | null>(null)
 const currentDept = ref<DepartmentOverview | null>(null)
 const scoreAdjustForm = reactive<ScoreAdjustPayload>({
@@ -1554,6 +1574,30 @@ const departmentUsers = computed(() => {
   })
 })
 
+// 过滤后的部门列表（用于搜索）
+const filteredDepartments = computed(() => {
+  if (!departmentSearchText.value || !departmentSearchText.value.trim()) {
+    return departments.value
+  }
+  
+  const searchText = departmentSearchText.value.trim().toLowerCase()
+  return departments.value.filter(dept => {
+    // 搜索部门名称
+    if (dept.deptName && dept.deptName.toLowerCase().includes(searchText)) {
+      return true
+    }
+    // 搜索部门编码
+    if (dept.deptCode && dept.deptCode.toLowerCase().includes(searchText)) {
+      return true
+    }
+    // 搜索负责人名称
+    if (dept.leaderName && dept.leaderName.toLowerCase().includes(searchText)) {
+      return true
+    }
+    return false
+  })
+})
+
 const hasUserData = computed(() => {
   return unassignedUsers.value.length > 0 || departmentUserCards.value.some((dept) => dept.users.length > 0)
 })
@@ -1832,6 +1876,12 @@ const filterUserOption = (input: string, option: any) => {
   return realName.includes(searchText) || username.includes(searchText)
 }
 
+// 部门搜索处理
+const onDepartmentSearch = () => {
+  // 搜索逻辑通过 computed 属性 filteredDepartments 自动处理
+  // 此方法仅用于响应搜索事件，实际过滤在 computed 中完成
+}
+
 // 显示积分池管理弹窗
 const showScorePoolModal = async (dept: DepartmentOverview) => {
   if (!dept.id) return