On main, the `RENDERER` and `PARSER` fields from the `Modelfile` don't
get propagated to a new model created with a `req.From` parameter. This
is easily triggered via `ollama run qwen3-coder`, then running some save
command like `/save qwen3-coder-custom`.
Added a regression test for this, and then open the config for the
"from" model in order to use its renderer/parser as a default for the
new model. This will fix the CLI and also API-based creates.
Fixes: https://github.com/ollama/ollama/issues/12792
1bdd816910