refactor(frontend): comprehensive architectural optimization and base component extraction

- Standardized table loading logic with enhanced useTableLoader.
- Unified form submission patterns via new useForm composable.
- Extracted common UI components: SearchInput and StatusBadge.
- Centralized common interface definitions in types/index.ts.
- Achieved TypeScript zero-error status across refactored files.
- Greatly improved code reusability and maintainability.

frontend/src/components/user/UserAttributeForm.vue

@@ -93,13 +93,10 @@
 
 <script setup lang="ts">
 import { ref, watch, onMounted } from 'vue'
-import { useI18n } from 'vue-i18n'
 import { adminAPI } from '@/api/admin'
 import type { UserAttributeDefinition, UserAttributeValuesMap } from '@/types'
 import Select from '@/components/common/Select.vue'
 
-const { t } = useI18n()
-
 interface Props {
   userId?: number
   modelValue: UserAttributeValuesMap