ACP loadSessionMode doesn't set model and mode

[noamzbr]

Description

First of all, sorry.. I've implemented a wrong fix to #7804 in #7809.

That fix correctly retrieves the model and mode from the last message, and returns them in the load response, but it fails to actually set the model and mode in the session - resulting in the session still using the default model.

What needs to be done - use setModel and setMode right after they are retrieved from the message

Plugins

No response

OpenCode version

v1.1.26

Steps to reproduce

1. Start a session, set model to non-default, send a message
2. Load the session.
3. Load session will return (correctly) non-default model in response
4. Send a message
5. Message is sent to default model

Screenshot and/or share link

No response

Operating System

macOS 15.6.1

Terminal

Ghostty

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• Model selection in UI is ignored - reverts to default model instead #9824: Model selection in UI is ignored - reverts to default model instead

Both issues describe problems with model selection not being persisted during session operations. Feel free to ignore if this doesn't address your specific case.