Entire chat being resent on every load

### What happened?

When OpenCode v2 is closed, and the last thing in the chat is a submit_plan, when OpenCode is reopened, the entire chat is resent. This causes a massive drain in tokens very quickly. I'm guessing this is due to the background server OpenCode now runs in their v2 version.

I've reported this to the OpenCode team, but they said it was an issue on the plugins end. I've seen this issue with multiple other plugins as well.

Let me know if I can provide any more details

### Plannotator version

v0.26.8

### OS

macOS

### Agent

OpenCode

### Where did it happen?

Plan review

Reproduce the issue in the Plan review flow with OpenCode v2: close OpenCode when the last chat item is submit_plan, then reopen it and observe whether the entire chat is resent. Compare this behavior with other plugins or agent flows if available; done means reopening does not resend the existing chat or cause the reported token drain.

Written by the indexing model from the issue text.