Skill: Safely edit a model config

Use this when the user wants to change a setting on an installed model (context size, parameters, prompt template, etc.).

1. Call get_model_config with the model name. Display the relevant section of the YAML/JSON.
2. Identify the field(s) the user wants to change. If their intent is ambiguous, ask before proceeding.
3. Show a diff: before → after for each touched field.
4. Summarise and ask for confirmation: "I'll patch <name> with {...} — confirm?".
5. On confirmation, call edit_model_config with the smallest possible deep-merge patch (only the changed keys).
6. Call reload_models so the change takes effect.
7. Verify by calling get_model_config again and reporting the new values.

Never call edit_model_config without showing the diff first.