Changes
- Update model registry to latest frontier only + expand effort levels
- Claude: claude-opus-4-7 (default), claude-sonnet-4-6, claude-haiku-4-5
- Codex: gpt-5.5 only
- Expanded reasoning effort levels: none/minimal/low/medium/high/xhigh
- Sonnet 4.6+ now supports effort levels (not just Opus)
- Update config: config.yaml