[FEATURE] max effort level cannot be persisted in settings.json

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

The max effort level works via /effort max and CLI flags, but cannot be saved persistently in settings.json — only low, medium, and high are accepted there. This means users must re-set it every session.

Proposed Solution

settings.json should accept "effortLevel": "max" so it persists across sessions, at least when using Opus 4.6.

Alternative Solutions

_No response_

Priority

Low - Nice to have

Feature Category

Configuration and settings

Use Case Example

_No response_

Additional Context

_No response_