fix: login persistence, username login, realtime refresh, group name uniqueness

- Remove loadFromCookie that overwrites valid localStorage auth data
- Set user status to idle on first login (was empty string)
- Default empty status to idle instead of away

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/api/pocketbase.ts

@@ -5,13 +5,7 @@ const pbUrl = import.meta.env.VITE_PB_URL || window.location.origin
 
 export const pb = new PocketBase(pbUrl)
 
-// 认证状态持久化
-pb.authStore.loadFromCookie(document.cookie)
-
-// 保存认证状态到 cookie
-pb.authStore.onChange(() => {
-  document.cookie = pb.authStore.exportToCookie({ httpOnly: false, path: '/' })
-})
+// SDK v0.21+ 自动使用 localStorage 持久化，无需手动 cookie 操作
 
 // 获取当前用户
 export function getCurrentUser() {

frontend/src/stores/user.ts

@@ -12,7 +12,7 @@ export const useUserStore = defineStore('user', () => {
 
   // 计算属性
   const isLoggedIn = computed(() => isAuthenticated() && user.value !== null)
-  const userStatus = computed(() => user.value?.status || 'away')
+  const userStatus = computed(() => user.value?.status || 'idle')
   const userId = computed(() => user.value?.id || '')
 
   // 初始化用户信息
@@ -41,6 +41,10 @@ export const useUserStore = defineStore('user', () => {
       loading.value = true
       await pb.collection('users').authWithPassword(email, password)
       await initUser()
+      // 首次登录设置默认状态为空闲
+      if (user.value && !user.value.status) {
+        await setStatus('idle')
+      }
     } catch (error: any) {
       throw new Error('邮箱或密码错误')
     } finally {