Ogma v0.3.0

Choose your model and reasoning effort. bin/setup now prompts for a model (curated sonnet/haiku/opus aliases or any full id; best-effort live list when ANTHROPIC_API_KEY is set) and an effort level. New chat commands /model and /effort change them live and persist to .env (mirrors Claude Code's built-in /model); the gateway passes --effort to the claude CLI. See CHANGELOG.md.