Add named permissions/approval presets for parity with built-in presets in /permissions menu

What variant of Codex are you using?

Codex CLI

What feature would you like to see?

Background

The built-in permissions/approval presets (Read Only, Ask for approval, Approve for me, Full Access) are shown together with presets derived from named permissions profiles (permissions.<name>) in the /permissions selector, but the built-in presets are currently richer:

1. Built-in presets can also change the approval policy.
2. Built-in presets can also modify the approvals reviewer.

Feature Request

Make it possible to effectively define named presets for /permissions that can specify approval policy and approvals reviewer together with the permissions profile to use. Either by extending the named permission profile feature or by introducing a new feature for named permissions/approval presets.

Motivation

I find the Never approval policy very useful together with the new named permissions profiles, as the profiles allow to specify rich enough permissions that the agent can do a lot of useful things without having to ask for further permissions. It is also a very secure and predictable mode that would be useful to recommend or require in a managed context. I can set the approval policy to Never in my configuration, but the built-in presets change it back to their preferred mode, and it's awkward to have to

Additional information

More concretely I'm asking for either of these sets of new configuration options:

1. Extended named permissions profiles

permissions.<name>.approval_policy
permissions.<name>.approvals_reviewer

1. New named permissions/approval presets

permissions_preset.<name>.permissions
permissions_preset.<name>.approval_policy
permissions_preset.<name>.approvals_reviewer
permissions_preset.<name>.extends = auto | read-only | full-access
default_permissions_preset

The second alternative would go best together with unifying the current "UI agnostic" builtin_approval_presets list with the TUI built-in presets in open_permission_profiles_popup, so that it's possible to reference and set as default also the approve_for_me and ask_for_approval presets directly, not auto which would otherwise awkwardly have to snap in the TUI to either of those based on the current approvals_reviewer.