Reuse the current session's selected model during config-time agent rebuilds when config.model is missing, so desktop sessions do not snap back to the default model after each send.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
Keep install-time and runtime model tables in sync, stop OpenAI-only misrouting when OpenCode Go is present, and add valid OpenAI fallbacks for atlas, metis, and sisyphus-junior.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>