feat: P3阶段完成 - 全部模块迁移完成 🎉

## P3.1: 争议仲裁模块（disputes）✅
- API: disputes.ts
- 模块导出

## P3.2: 卖家中心模块（seller）✅
- Views: 4个页面
- Composables: usePublishForm, usePublishDraft
- 模块导出

## P3.3: 管理后台模块（admin）✅
- API: 8个文件（adminAuth, adminDashboard, adminUsers等）
- Views: 15个管理页面
- Composables: useAdminTable, useAdminPaginatedTable
- Components: 管理端组件
- 模块导出

---

## 🎉 Features 架构迁移全部完成！

### 最终统计
- ✅ P0: shared（基础设施）- 22个文件
- ✅ P1: wallet, chats, orders - 24个文件
- ✅ P2: listings, auth - 35个文件
- ✅ P3: seller, disputes, admin - 47个文件

**总计：** 9个模块，128个文件完成迁移

### 新架构
```
frontend/src/
├── features/          # 9个业务模块 ✅
│   ├── wallet/       ✅
│   ├── chats/        ✅
│   ├── orders/       ✅ (已重构)
│   ├── listings/     ✅
│   ├── auth/         ✅
│   ├── seller/       ✅
│   ├── disputes/     ✅
│   └── admin/        ✅
└── shared/           ✅
```

下一步：清理旧文件、更新路由配置

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/features/admin/components/AssignRolesDialog.vue

@@ -0,0 +1,115 @@
+<script setup lang="ts">
+import { ElMessage } from 'element-plus'
+import { ref, watch } from 'vue'
+
+import { fetchRoles, type Role } from '@/api/adminRoles'
+import { assignAdminRoles, type AdminMgrUser } from '@/api/adminMgr'
+
+const props = defineProps<{
+  modelValue: boolean
+  admin: AdminMgrUser | null
+}>()
+
+const emit = defineEmits<{
+  (e: 'update:modelValue', val: boolean): void
+  (e: 'saved'): void
+}>()
+
+const submitting = ref(false)
+const loading = ref(false)
+const allRoles = ref<Role[]>([])
+const selectedRoleIds = ref<number[]>([])
+
+watch(
+  () => props.modelValue,
+  async (val) => {
+    if (val && props.admin) {
+      loading.value = true
+      try {
+        allRoles.value = await fetchRoles()
+        selectedRoleIds.value = props.admin.roles.map((r) => r.id)
+      } catch {
+        ElMessage.error('加载角色列表失败')
+      } finally {
+        loading.value = false
+      }
+    }
+  },
+)
+
+async function handleSave() {
+  if (!props.admin) return
+  submitting.value = true
+  try {
+    await assignAdminRoles(props.admin.id, selectedRoleIds.value)
+    ElMessage.success('角色已分配')
+    emit('saved')
+    emit('update:modelValue', false)
+  } catch (error) {
+    ElMessage.error(readError(error, '分配失败'))
+  } finally {
+    submitting.value = false
+  }
+}
+
+function readError(error: unknown, fallback: string) {
+  if (typeof error === 'object' && error && 'response' in error) {
+    const response = (error as { response?: { data?: { message?: string } } }).response
+    return response?.data?.message || fallback
+  }
+  return fallback
+}
+</script>
+
+<template>
+  <el-dialog
+    :model-value="modelValue"
+    :title="`分配角色 - ${admin?.username || ''}`"
+    width="500px"
+    @update:model-value="emit('update:modelValue', $event)"
+  >
+    <div v-loading="loading" class="dialog-body">
+      <p v-if="admin" class="admin-info">
+        <strong>{{ admin.username }}</strong> · {{ admin.nickname }}
+      </p>
+      <el-checkbox-group v-model="selectedRoleIds">
+        <div v-for="role in allRoles" :key="role.id" class="role-option">
+          <el-checkbox :value="role.id" :label="role.id">
+            <span class="role-name">{{ role.name }}</span>
+            <span class="role-desc">{{ role.description }}</span>
+          </el-checkbox>
+        </div>
+      </el-checkbox-group>
+    </div>
+    <template #footer>
+      <el-button @click="emit('update:modelValue', false)">取消</el-button>
+      <el-button type="primary" :loading="submitting" @click="handleSave">保存</el-button>
+    </template>
+  </el-dialog>
+</template>
+
+<style scoped>
+.dialog-body {
+  display: grid;
+  gap: 16px;
+}
+.admin-info {
+  margin: 0;
+  color: #374151;
+}
+.role-option {
+  padding: 8px 0;
+  border-bottom: 1px solid #f0f0f0;
+}
+.role-option:last-child {
+  border-bottom: none;
+}
+.role-name {
+  font-weight: 500;
+  margin-right: 8px;
+}
+.role-desc {
+  color: #8f9bba;
+  font-size: 13px;
+}
+</style>