[Feature Request] Add 1M token context window option for Claude 3.5 Opus in OpusPlan

Question

**Bug Description**
I’d like to see the Opus context in OpusPlan expanded to support up to 1M tokens.
Additionally, it would be great if this option could be included in the default selection list.

I believe this change alone would be helpful for quite a number of users.

**Environment Info**
- Platform: darwin
- Terminal: tmux
- Version: 2.1.90
- Feedback ID: da39a292-00d8-4dd0-93fa-06f3829753ca

**Errors**
```json
[]
```