Add new privilege definitions:
- LLMConfig.Audit - View LLM model configurations
- LLMConfig.Modify - Update LLM model configurations
- LLMConfig.Allocate - Create/delete LLM model configurations
Add LLMConfig.Audit and LLMConfig.Modify to default User role so that
regular users can manage their own AI profiles without needing the
User.Manager role.
User-scoped LLM config endpoints now use LLMConfig.* permissions.
Group-scoped LLM config endpoints retain Group.* permissions.
