fix: sync user status changes across team lifecycle

- Accept invitation: update local userStore status to in_team
- Start game: update userStore status to in_team
- End game: update userStore status to idle, simplify endGame logic
- Add $autoCancel:false to endGame session fetch

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

frontend/src/api/invitations.ts

@@ -100,6 +100,13 @@ export async function respondInvitation(
 
     // 更新用户状态为 in_team
     await pb.collection('users').update(user.id, { status: 'in_team' })
+
+    // 同步更新本地 userStore
+    const { useUserStore } = await import('@/stores/user')
+    const userStore = useUserStore()
+    if (userStore.user) {
+      userStore.user.status = 'in_team'
+    }
   }
 
   // 更新邀请状态