v0.19.0

Added

• Skills system: Auto-discover and load instruction files on-demand. Supports Claude Code (~/.claude/skills/*/SKILL.md), Codex CLI (~/.codex/skills/), and Pi-native formats (~/.pi/agent/skills/, .pi/skills/). Skills are listed in system prompt with descriptions, agent loads them via read tool when needed. Supports {baseDir} placeholder. Disable with --no-skills or skills.enabled: false in settings. (#169)

• Version flag: Added --version / -v flag to display the current version and exit. (#170)