Claude 上线了 1m context，为什么我这用不了啊？
https://code.claude.com/docs/en/model-config#extended-context-with-1m
已经升级最新版 v2.1.76 ，用的时候还提示：
Opus 4.6 with 1M context is not available for your account. Learn more: https://code.claude.com/docs/en/model-config#extended-context-with-1m