fix(前端): 修复 ESLint 代码规范问题

- 修复 AccountTableFilters.vue 中的 vue/no-mutating-props 错误，使用 emit 模式替代直接修改 props
- 修复 TypeScript 类型错误，支持 Select 组件的 null 值类型
- 为所有空 catch 块添加错误日志，提升代码可维护性和调试能力
- 涉及文件：AccountTableFilters.vue, UserAllowedGroupsModal.vue, UserApiKeysModal.vue, UserBalanceModal.vue, AccountsView.vue, UsageView.vue, DashboardView.vue, ProfileView.vue

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

frontend/src/components/admin/user/UserApiKeysModal.vue

@@ -42,6 +42,6 @@ const apiKeys = ref<ApiKey[]>([]); const loading = ref(false)
 watch(() => props.show, (v) => { if (v && props.user) load() })
 const load = async () => {
   if (!props.user) return; loading.value = true
-  try { const res = await adminAPI.users.getUserApiKeys(props.user.id); apiKeys.value = res.items || [] } catch {} finally { loading.value = false }
+  try { const res = await adminAPI.users.getUserApiKeys(props.user.id); apiKeys.value = res.items || [] } catch (error) { console.error('Failed to load API keys:', error) } finally { loading.value = false }
 }
 </script>